192 [July, 1842. 



feet insect visibly differs, and the habits of the larva vary materially in respect to 

 food and habitation. We copy some of the characters. 



1. Chirnomides. Aquatic Tipulides. Male antennae plumose ; larva) aquatic. 



2. Tipulides proper. Terrestrial Tipulides. Head elongated into a muzzle; 

 no ocelli ; larva? inhabit the earth. 



3. Mycetophilides. Tipulides of fungi. Two or three ocelli ; trochanters 

 elongated ; tibiae strongly spurred ; larva? feed on fungi. 



4. Cecidomyides. Tipulides of gall-nuts. Head not prolonged into a muzzle ; 

 no ocelli ; trochanters of ordinary length ; antenna? moniliform ; larva? feed in 

 galls formed on vegetable substances. 



5. Bibionides. Tipulides of flowers. Antenna? short, perfoliatcd, generally fewer 

 than 12 joints ; legs of ordinary length ; larva? often resident in rotten dung 

 and vegetable debris. [To me, this seems contradictory.] 



The above classification is quoted from M. Latreille ; and is preferred by the 

 author whom I have already cited, and whom I believe to be Mr. Westwood. The 

 less extensive knowledge of the species possessed in the years when Messrs. Meigen 

 and Lamarck wrote, prevented their distribution of the family from being, at that 

 time, so perfect. They are compelled, in this place, to follow a more artificial 

 method ; and have thus brought in close approximation some animals whose mode 

 of life has subsequently been thought to differ. It has since been thought to be 

 rendered evident, that the larva? of the proper tipulida?, at least as a general rule, 

 live on the roots of plants. Among the authorities cited for this are Kirby and 

 Spcnce. 



It is evident that the natural affinities of Cecidomyia, are with the sub-family 

 to which it has given its name. It has been approximated to Lasioptera. The 

 latter is a genus with terrestrial larva?, living on roots ; and the parent, according 

 to professor Meigen, not furnished with an ovipositor. The figures, too, given by 

 the latter writer as specimens of the genera, differ in their habitus. In the earlier 

 state of knowledge in relation to the tipulide tribe, and particularly while the lar- 

 va? were less known, the collocation of several species was doubtful. Mr. Meigen 

 is said to place the tipula juniperina L., which inhabits the tops of the juniper, 

 " doubtfully in Lasioptera." 1 understand the words " unbekannte horde," under 

 which he introduces this species, to mean " unknown, or ill-understood horde," or 

 " unknown, ill-defined group." 



it is observed that every larva of the family, thus fur, appears to consume solid 

 substances by chewing, and, as a necessary inference, to possess real jaws; instead 

 of sucking by a trunk, as has been, in this country, universally affirmed of the 

 species so frequently the subject of popular discussion. The consideration goes to 

 strengthen, if possible, the inference that the quiescent substance generally sup- 

 posed, in imitation of Mr. Say, to be the larva of the Hessian fly, and which, by 

 the avowal of that distinguished writer, so closely resembles the pupa, is really the 

 pupa in an earlier stage, and that the larva is to be looked for in the maxillated 

 and gnawing worm. 



It appears to be every where observed, that as soon as these animals increase 

 to a certain extent, their further diffusion is immediately limited by the ravages 

 of the different parasites of the families Chalcidida? and Proctotrupida?. The 

 coincidence of these diminutions, from a cause not generally understood, with 

 various other circumstances affecting the wheat crops, probably gives reputation 

 to many other supposed means, natural and artificial, of destroying the injurious 



The Corresponding Secretary read several letters from Mr. 

 Couper, of Georgia, addressed to Dr. Harlan of this city, in 



