1847.] Insects Injurious to Vegetation. 9 



cies are translucent, and of a membranous texture. In the Hes- 

 sian fly, however, it becomes opake, changes its color, and is of a 

 firm or coriaceous texture. The inclosed worm, also, does not 

 leave it, but remaining, eventually changes within it to a pupa, 

 the same case thus forming its puparium. Its metamorphosis thus 

 approximates it to the Muscidce or true flies, the Stratiomidae or 

 soldier-flies, &c. and its pupa, in technical language is "coarctate" 

 and not "incomplete" like the pupae of the other cecidomyians. 

 Should usage therefore settle down upon the name midge as dis- 

 tinctive of the minute tipulides, there will still be a marked pro- 

 priety in continuing to this species its old name, Hessian ^fly* 



The Fly. Its Characters. — In the female, (fig. 3,) the head is 

 flattened globular, and black throughout. The antenna (fig. e,) 

 are about half as long as the body, and composed of sixteen 

 joints, each of a cylindric-oval form, the length being about dou- 

 ble the diameter; each joint is clothed with a number of hairs, of 

 which those towards its base are slightly more robust and longer, 

 about equalling the joint In their length, and surrounding it in a 

 whirl. The joints are separated from each other by very short 

 translucent filaments, having a diameter about a third as great as 

 the joints themselves. The terminal joint is at least a third longer 

 than the preceding ones. The two basal joints of each antenna 

 are globular, and compact or not separated by an intervening fil- 

 ament, and exceed the following joints in diameter. The falpi 

 (fig. y,) consists of three obvious joints, clothed with very short 

 minute hairs. The two last joints are cylindrical, nearly equal 

 in size, and about twice as long as broad: the basal joint is more 

 short and thick. The thorax is oval, broadest immediately back 

 of the wing-sockets, and black. The scutel is of the same color, 

 projecting, and slightly polished, with the suture surrounding it 

 sometimes fulvous. The poisers are (kisky. The abdomen is 

 elongate-ovate, its broadest part scarcely equalling the thorax in 

 diameter; it is of a black color above, more or less widely mark- 

 ed at the sutures with tawny-fulvous, and furnished with numerous 

 fine blackish hairs. The ovipositor is rose-red, and slightly ex- 

 serted commonly in the dead specimen; it is susceptible of being 

 protruded to a third of the length of the abdomen. The uings 



*I dnubt, however, whether the Hessian fly will continue to he the sole 

 member of this ceniis havin? a coarctate pupa. Quite recently a species lias 

 occurred to my notice, analasous to the Hessian fly flax seed in every point 

 that I have been able to delect, except that its larva case is of a pale brown 

 color, unlinked with rul'nus or casianeous. It infests the Jgroiiis laterifo- 

 ra?, numbers dwellins tosether in an imbricated sail, somewhat n^(nil,ling 

 the fertile aments of the hop, though larger, and connected with the main 

 stalk by a short pedicel which is inserted into one of the lowest joints ot the 

 culm. From the coriaceous texture of the larva case, I suspect the inclosed 

 worm will not leave it, until transformed to a pupa and upon the point of 

 evolving the perfect fly. 



