June, '08] ENTOMOLOGICAL NEWS. 277 



that a close relation exists between the two forms. My 

 material of Ps. floridica has deteriorated considerably, especially 

 the larvae and adults, so that comparisons in some particular 

 details are made with considerable difficulty. 



There is a very marked difference in the size of the Missouri 

 and Florida specimens, the larva? of the latter being from one- 

 fourth to one-third larger. The difference in size also appears 

 in the pupae and adults. The Florida larv?e have eight or nine 

 dorsal plates on the posterior annuli of the abdominal segments, 

 while the Missouri larvae have but six. The Florida larvae 

 have no ventral thoracic plates, while the Missouri ones have 

 two small widely separated plates on the posterior annulus of 

 each segment. Each of these plates bears two long bristling 

 hairs. In the living Missouri larvae the internal organs show 

 through the body wall as a broad creamy-white band in the 

 region of the fourth and fifth abdominal segments, which did 

 not appear in the Florida larvae. These slight but uniformly 

 constant differences convince me that this Missouri Psychodid 

 is not the same as the Florida one, though certainly very closely 

 related. The adults have been compared with Ps. noctnrnala 

 and their similarity in every respect is so great that I feel sure 

 they are the same species. The dates of their appearance also 

 correspond. 



I find that my figures of Ps. floridica are slightly at fault 

 on the segmentation of the posterior end of the abdomen. In 

 some cases I find that the break between the last two annuli 

 is so marked that I mistook it for a segmental rather than an 

 annular division. 



LARVA. 



The larva is quite slender, cylindrical, measuring 11 mm. 

 in length and .8 mm. in breadth. Each of the three thoracic 

 segments is rather distinctly divided into two annuli. The 

 first abdominal segment also has two annuli, while each of the 

 other six abdominal segments has three. Each annulus of the 

 two posterior abdominal segments has, on its dorsal surface, a 

 small chitinous shield; the third shield of each segment being 



