520 MODERN CLASSIFICATION OF INSECTS. 
Hessian fly, has been described and figured by Say, under the name 
of C. destructor; it attacks the lower part of the stem of the plant. 
When full grown, it becomes a pupa enclosed in a covering, at which 
time it is known under the name of the flax-seed state (fig. 125. 8.). 
It is not described in what manner this case is formed. The species 
differs in this respect materially from its congeners. (See also Dry- 
ander’s Catal. Library Banks.) The same, or a closely allied species, 
has been observed by Dr. Hammerschmidt of Vienna, by whom 
specimens were forwarded to M. Lefebvre, who presented them to 
me. (See Kollar’s Treatise on Injurious Insects, transl. p. 118.) On 
opening some of the cases, I discovered the larve enclosed dead, and 
in a shrivelled state. 
Another species, T. pennicornis, effects the impregnation of the 
flowers of Aristolochia (Willdenow, Grundr. d. Krauterkunde, p. 353., 
Introd. to Ent. vol. i. p. 298., and Ann. Med. Rev. vol. ii. p. 400.). M. V. 
Audouin has communicated to me an observation made by himself on 
a species which lives in the leaves of Buxus —?, the pupa of which 
pierces the epidermis of the leaf, thrusting the front of the body 
into the air immediately before assuming the perfect state. It is dif- 
ficult to conceive how the delicate species which are bred in the hard 
woody galls make their escape. 
I regret that want of space will only permit me to notice the fol- 
lowing additional memoirs upon various species of Cecidomyia: L. 
Dufour on C. Erice (in Ann. Soc. Ent. de France, 1837, p. 83., and 
in ditto, 1838, p. 293., C. Pint maritime) ; Bouche’s descriptions of the 
larvee and pupe of several species, in his Naturgeschichte (tab. 2.) ; 
Vallot on Cecidomyia Pow ; and its parasite, in the Ann. des Sci. 
Natur. July, 1833 ; Géné,*on C. Hyperici, in the Trans. of the Turin 
Acad. vol. xxxvi.; P. F. H. Baddeley, Esq., on an East Indian species 
of this genus which produces a kind of gall on the leaves of Ficus race- 
mosa, illustrated by beautiful figures in Corbyn’s India Review, No. 7. 
Oct.-15. 1836; Drewsen in Ann. Soc. Ent. de France, 1835, p. \xii. 
The singular genus Psychoda (forming the tribe Phalenoides Mcq. ) 
composed of minute species, with broad, deflexed, and very hairy 
wings (fig. 125.9—10. head and antenna), often found on windows, 
although agreeing with this subfamily in the elongated antennz, com- 
posed of globular verticillated joints, differs in the greater number of 
the veins of the wings. The larva of P. Phalenoides, figured by 
Bouché (Naturgesch. tab. 2. f. 20.), resides in dung ; it is long, sub- 
