204 



Hessian Fly. 



Vol. V. 



" chrysallis," was the Greek for a molli, and 

 meant a " thing of a golden colour." 



The words " perfect insect" are now gene- 

 rally employed to express tliese animals when 

 Ihey have undergone the last developments 

 of which their nature is capable ; and it is in 

 this state that they have been sometimes, 

 perhaps unnecessarily, called " imago," the 

 image. These terms require no explanation. 

 It is in this stage that the females deposit 

 their eggs. 



Experience has shown that, in describing 

 the many thousand kinds of insects met with 

 by naturalists, the purposes of classification 

 and distinction cannot be well answered with- 

 out making new names from the Greek lan- 

 guage for nearly every newly described ge- 

 nus or family, and adding a Latin adjective 

 or substantive, to express the species or more 

 particular kind. One reason, in itself very 

 sufficient in the present case, and which may 

 serve for an example, is that the animal 

 called Hessian Fly is not Hessian at all, but 

 an insect produced only in America. Thomas 

 Say found it to belong to a genus called by 

 high authorities, Cecidomyia ; and has him- 

 self called this American species, destructor. 

 Cecidomyia expresses, in Greek, "smelling- 

 fly" or otherwise " nutgall-fly ;" from kekis, 

 in Latin and English spelled cecis, which 

 means both a smell and a nutgall, and myia, 

 a fly. We are not entomologists enough to 

 know which of these two meanings was de- 

 signed to be conveyed by the word. The fly 

 is a Tipulide insect, or one resembling the 

 Tipula or " water-spider," that walks on run- 

 ning water, repelling the fluid with its feet ; 

 and is a two-winged fly, with poisers or 

 •weights. We subjoin the description of the 

 perfect insect, from Mr. Say; which we can 

 neither abridge nor convert into popular lan- 

 guage. Besides accommodating those among 

 our readers who have an acquaintance with 

 entomology, it may serve to show the great 

 accuracy sometimes necessary in distinguish- 

 ing these little beings. 



" Order DIPTERA. Genus Cecidomyia, 

 Latreille and Meigen. 



Tipula, Linn, and Degeer. Chironomus, 

 Fabricius. Trichocera, Lamarck. 



AntenniB filiform, joints subequal, globu- 

 lar, hairy. Proboscis salient. Wings in- 

 cumbent, horizontal, 



Cecidomyia destructor. Head and thorax 

 black ; wings black, fulvous at base ; feet 

 pale, covered with black hair. 



Inhabits the northern and middle States. 



Body clothed with short, black hairs. Head 

 black. AntenncB shorter than the body, some- 

 what smaller towards the tip, verticillate, 

 joints moniliform, separated by a hyaline fila- 



ment. Thorax gibbous, black, glabrous and 

 polished. Scutel prominent, colour of the 

 thorax, rounded behind. Wings ciliate, 

 rounded at tip, blackish ; — the fulvous colour 

 of the base is sometimes extended upon the 

 nerves of the wing, paler and gradually dis- 

 appearing before the middle; longer than the 

 abdomen. Feet long, slender, thighs ful- 

 vous at base, furnished, at the tip, with seve- 

 ral very acute claws. Poisers pale, nearly 

 as long as the thorax, with a suboval capitu- 

 lum. Breast sometimes fulvous. Abdomen 

 brownish. 



Female. Antenn(B longer than the thorax, 

 the joints somewhat oval, not separated by 

 filaments. Abdomen elongate-oval, above 

 rectilinear, beneath somewhat ventricose, ful- 

 vous, with a dorsal and ventral black vitta 

 widely interrupted by the sutures. Tail 

 more or less acute in the dead specimen in 

 proportion as the oviduct is exserted. Length 

 rather more than three twentieths of an inch. 



Eggs elongated, linear, pale-fulv-ous." 



The description of the pupa, so familiar 

 under tiie name of the flaxseed state, we will 

 omit ; and Mr. Say makes the larva the same 

 as the pupa, with the exception of a mode- 

 rate difference in colour, and a little more 

 motion. This, according to the views of 

 Miss Morris, will be held to be the early por- 

 tion of the pupa stage. 



We learn, upon the authority of Miss Mor- 

 ris, that this fly is seen buzzing about the 

 ears of the growing wheat ; in the seeds of 

 which it deposits its eggs. The very com- 

 mon belief that it is the animal found busy 

 about the roots, is owing to the Ceraphron, 

 which we mean next to describe, being mis- 

 taken for it; an error which the statement 

 of Mr. Say, that the real Hessian Fly de- 

 posits its eggs under the sheath of the leaf, 

 is liable to encourage. 



The Ceraphron destructor, which has thus 

 been mistaken for the Hessian Fly, is an 

 Ichneumonide insect, or one of that numerous 

 class that deposit their eggs in the bodies of 

 others; and would, according to the less ex- 

 extended arrangements of earlier naturalists, 

 have been, itself, called an Ichneumon. The 

 injury we have just described, it actually in- 

 flicts on the Hessian Fly, and it is thus the 

 mortal enemy of the animal for which it has 

 been mistaken; an error not very uncom- 

 mon. In the words of Mr. Say, " it seems 

 probable that this insect prevents the total 

 loss of our wheat crops by restraining the 

 increase of the cecidomyia within certain 

 bounds. True to the manners of its kind, 

 the parent deposits her eggs within the bo- 

 dies of the larvse [considered by Miss Mor- 

 ris, pupffi,] of the Cecidomyia destructor, 

 through a puncture made by her acute ovi- 

 duct, for the purpose. The young, when dis- 



