Usinger, R.L.

Proceedings of the Hawaiian Entomological Society

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271Distribution and Host Relationships of Cyrtorhinus(Hemiptera: Miridae)BY ROBERT L. USINGBRCalifornia Academy of Sciences(Presented by Mr. Fullaway at the meeting of Dec. 1, 1938)As the genus Cyrtorhinus Fieber seems destined to play an increasingly important role in the biological control of Delphacid leaf-hoppers it is of interest to examine its distribution and host relationships. Present records suggest that the group may eventuallyprove to be cosmopolitan, the paucity of records from Central andSouth America, Australia, and Africa very possibly being due tothe fragmentary state of our knowledge of the Mirid fauna of* theseregions.Although known from Europe since 1807 (caricis Fallen) andfrom the East Indies since 1884 (lividipennis Reuter) no memberof the genus was recorded from North America until 1916 (caricisvar. vagus Knight) while the predatory habits of the group were notdiscovered until 1920. At this time Muir's discovery that Cyrtorhinus mundulus (Breddin) lives exclusively on the eggs of theSugar-cane Leafhopper, Perkinsiella saccharicida Kirkaldy, led toone of the most outstanding successes in the field of biological control of injurious insects.Delphacids imbed their eggs in rows either along the stems ormidribs of the leaves of their preferred hosts. The eggs are inserted in a slit and directed obliquely with one end at the surface ofthe plant tissue. Cyrtorhinus, although belonging to a predominantly phytophagous subfamily, Orthotylinae, of the great plantfeeding family Miridae, has evidently turned to an exclusively predatory life, piercing the eggs of these leafhoppers and sucking outtheir juices. Even when apparently inserting the beak intounbroken plant surfaces I have always found that a leafhopper eggwas the objective, perhaps having been laid from the opposite sideof the leaf. I have shown1 that the change, even from plant feeding to sucking the blood of human beings is not so fundamental asit might at first appear and Esaki^actually records facultative bloodsucking in Cyrtorhinus lividipennis Reuter.In recent years field records would indicate that these bugs,although showing a marked preference for a particular plant andits associated Delphacid eggs, may turn to related plants and leaf-hoppers in the vicinity as occasion or opportunity affords. Thus Ii usinger, R. L. Bloodsucking among phytophagous Hemiptera. Can. Ent.,ftft • Q7_100 19^4a'Esaki; T. A case of the facultative "blood-sucking" in Cyrtorhinus liyidipennisReuter with notes on the same habit in some Typhlocybinae. Mushi, 7: 97-100,1934.Proc. Haw. Ent. Soc, X, No. 2, December, 1939.272found mundulus nymphs and adults occasionally on corn andSwezey and Fullaway found this same species on taro in the Hawaiian Islands while lividipennis was observed on sugar cane onGuam but only when the cane was growing near or in betweenplantings of corn. This characteristic adds greatly to the value ofCyrtorhinus bugs in biological control for it enables them to surviveafter completely wiping out their preferred host in a given area. Itis encouraging that mundulus has shown no tendency as yet to invade the native forest in Hawaii where a rich endemic populationof Delphacids flourishes.An apparent structural anomaly in Cyrtorhinus which has notbeen given sufficient attention is the absence, in certain species, ofarolia between the claws. In such cases two very fine, small, parallelsetae are the only structures to be seen between the claws. Thepresence or absence and form of the arolia is usually a very reliableguide to relationships in the Miridae, having been used by bothReuter and Knight in defining major groups within the family.Poppius first pointed out the absence of these structures in his twoFormosa species and in mundulus. They also appear to be lackingin riveti.Mr. D. T. Fullaway has recently sent for identification, throughMr. O. H. Swezey, specimens of Cyrtorhinus fulvus Knight, aspecies which has been introduced into Hawaii during the past yearin an effort to control the Taro Leafhopper, Megamelas proserpinaKirkaldy. As much as two years ago, after carefully observing itshabits and rearing a number of specimens on Guam and in thePhilippines, I suggested that lividipennis be considered for introduction into the Hawaiian Islands to control the Corn Leafhopper,Peregrinus maidis (Ashmead). There is some indication that thismay actually be done in the near future.DISTRIBUTION OF CYRTORHINUS SPECIES ACCORDING TO Z00GEO-GRAPHICAL REGIONSPalaearcticcaricis Fallenflaveolus Reutergeminus Florparviceps Reuterpygmaeus Zett.var. insignis D. & S.Orientalannulicollis Poppiuschinensis Stalelongatus Poppiusfulvus Knightlividipennis Reutermundulus BreddinNearcticalboornatus Knightballi Knightcaricis Fallenyar. vagus Knightinsperatus Knightpubescens Knightpygmaeus Zett.Australianmundulus BreddinNeotropicalcostae Stalpellicius UhlerAfricanmelanops ReuterPacificfulvus Knightlividipennis Reutermundulus Breddinriveti Cheesman273DISTRIBUTION OF PACIFIC ISLAND SPECIES3fulvus lividipennis mundulus riveti♦Philippine I. Great Nicobars Australia TahitiSamoa Formosa Java Samoa♦Java Java Philippine I. ♦GuamHawaii (1937) Ceylon Fiji I.Burma Hawaii (1920)SumatraJapan♦Guam♦Philippine I.♦ChinaPLANT AND LEAFHOPPER HOST RECORDS FOR PACIFIC SPECIES3mundulus lividipennisPerkinsiella saccharicida Kirk, on *Peregrinus maidis (Ashmead) onSugar Cane (preferred host). Corn (preferred host) (Guam*Peregrinus maidis (Ashmead) on and Luzon, P. I.).Corn (Hawaii). On Sporobolus grass (Samoa,Megamelas Proserpina Kirk, on Swezey and Wilder).Taro (Hawaii). Nilaparvata lugens (Stal) on Rice(Guam, Swezey).fulvus riveti*Megamelas proserpina Kirk, on *Sogata ochrias (Kirk.) on Sporo-Taro (preferred host) (Philip- bolus virginicus (Guam, Swezeypines, Fullaway). and Usinger).On Taro (Samoa, Swezey & On Bermuda grass (Samoa, Swe-Wilder). zey and Wilder).Tradescantia (Tahiti, Cheesman).*Nilaparvata lugens (Stal) on RiceGuam, Swezey).KEY TO PACIFIC ISLAND SPECIES OF CYRTORHINUS1. A pair of distinct diverging and then converging arolia between theclaws. .Head with a more or less distinct pattern formed by broadpale areas contiguous to inner margins of eyes on either side and sometimes meeting at center, always joined along posterior elevated marginbefore neck 2-. Two very fine, small, parallel setae between the claws. Head with amore or less distinct pale spot on either side of vertex contiguous withinner margins of eyes ; 32. Length to tip of membrane three times the greatest width across heme-lytra. Pale areas of upper surface fulvous and limited largely to thevertex, pronotum occasionally obscurely on the callosities and at middleof posterior margin, scutellum on either side of median black stripe,and hemelytra fulvus Knight-. Length less than three times the greatest width across hemelytra. General color much paler, ochraceous to green, with fuscous or blackmarks limited mainly to anterior portion of head, sides of posteriorlobe of pronotum, and middle of scutellum .lividipennis Reuter3. Body form long and slender. Size large, the length 3.08 to 3.42 mm.and width 1.05-1.12 mm. Hemelytra pale only laterally. First anten-nal segment fulvous mundulus Breddin-. Body form relatively short and oval. Size smaller, the length 1.87 to2.33 mm. and width 0.73 to 0.94 mm. Hemelytra often pale fuscous orlighter throughout. First antennal segment black .. .riveti Cheesman8 New records marked with an asterisk41.

Distribution and Host Relationships of Cyrtorhinus (Hemiptera: Miridae)

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Distribution and Host Relationships of Cyrtorhinus (Hemiptera: Miridae)

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