184 JASSID^. 



Geuus IDIOCEEUS. 



Idiocerus, Letvis, Trans. Ent. Soc. i, p. 47 (1836) ; Fieh. Rev. Mag. 

 Zool. (3) iii, p. 387 (1875) ; Van Diizee, Trans. Am. Ent. Soc. xxi, 

 p. 2G0 (1894); Osb. ^- Ball, Proc. Davcnp. Ac. Nat. Sci. vii, 

 p. 124 (1898) ; Melich. Horn. Faun. Ceylon, p. 146 (1903). 



Type, I. adustus, H.-S., a Palsearctic species. 



Distribution. Nearctic, Palseai'ctic and Oriental Eegions. Pro- 

 bably much more widely distributed. 



Osboru and Ball in their review of the North American species 

 of Idiocerus have so clearly diagnosed the genus that tbeir 

 description may be well reproduced. 



" The members of this genus are easily recognized by their large 

 size, broad short heads, the eyes exceeding the pronotum in width, 

 which in turn exceed that of the narrow apices of the folded 

 tegmina, giving the insects a wedge-shaped appearance. The 

 vertex is short and parallel-margined, rounding in front to the 

 face ; ocelli on the face between the eyes, just above the origin of 

 the frontal sutures ; the male antenuje usually bear a disc-like 

 swelling near the tip, this is wanting, however in a few of the 

 European and a number of the American species ; the tegmina are 

 usually longer than the abdomen and rather narrowly folded 

 behind; there is but one transverse nervure betv^-een the sectors 

 and that is often wanting in /. cratcegi* four apical and three 

 anteapical cells being the typical number ; the tegmina always 

 possess a distinct appendix and the supernumerary cell is present 

 in the wings." 



According to Osborn and Ball, " as far as known all the species 

 are two-brooded, the adults hibernating and depositing eggs in 

 spring. In the case of cdtematus * the eggs are placed near the 

 tip of the younger twigs, usually several in a place, often causing 

 distortion or death to the part." 



In ' Indian Museum Notes,' vol. i, no. 1, p. 4, Mr. Gollan, of 

 the Botanical Gardens at Saharanpur, gives particulars as to the 

 habits of three species which were subsequently identified as 

 /. clypealis, JjQth., niveosparus, Leth.,and atlinsoni, Leth. "They 

 are found upon the mango all summer, but do most harm when 

 the trees are in flower by damaging the reproductive organs, and 

 thus causing interference with the setting of the fruit. I have 

 tried mixtures of soap, tobacco, sulphur, kerosine diluted with 

 milk, &c. upon them, but without noticeable effect. We have not 

 had many of them this year (18S8?), but there are a few upon 

 some of the trees and quite sufficient of them to experiment with. 

 Last year, and the year before, we had them in myriads, and both 

 these seasons we had light crops of fruit, but this year a fine crop 

 has set, and this I attribute to the comparative absence of these 

 insects." 



A Nearctic species. 



