208 NEW YORK STATE MUSEUM 



distally, joining the margin at the apex of the wing; fifth vein sim- 

 ple, obsolete distally. Coxae, femora and tibiae fuscous yellowish, 

 the tarsi tinged with red ; claws rather long, evenly curved, simple, 

 the pulvilli about half the length of the claws. Genitalia; basal 

 clasp segment short, stout, obliquely truncate apically ; terminal 

 clasp segment short, stout, swollen subapically and with a heavy, 

 chitinous spur at the internal distal angle ; dorsal plate apparently 

 short, triangularly emarginate, the lobes broadly rounded and 

 sparsely setose ; ventral plate apparently moderately long, stout, 

 broadly rounded and sparsely setose apically; style short, stout, 

 narrowly rounded distally. 



Life history. Reproduction by pedogenesis occurs in the fall and 

 early spring, and under certain conditions apparently throughout 

 warm weather, though adults are usually produced from the latter 

 part of I\Iay to August. Under favorable conditions it appears 

 probable that pedogenesis may continue indefinitely. A larval gen- 

 eration occupies about 3 to 3^ weeks, much depending upon moist- 

 ure, food and temperature. The transformations to the adult are 

 preceded by the development of a distinct breastbone, this usually 

 occurring in early Alay. The change is soon followed by the ap- 

 pearance of the prepupa, characterized by a marked swelling and 

 transparent condition of the anterior body segments of the larva, 

 and in 2 or 3 days by the development of the pupa, a stage lasting 

 about 6 days. The small midges appear in immense numbers during 

 the late morning hours, namely from about 9 a. m. until noon, 

 swarming OA'er the sides of the jar and behaving much like minute 

 ants. There is comparatively little tendency to take wing. The de- 

 velopment of adults may continue for several days and the midges 

 may appear in smaller numbers for a period of several weeks. The 

 large eggs, well formed in the abdomen of recently transformed 

 females, are presumably deposited shortly and another succession 

 of larval generations begun. 



Natural enemies. iMiastor is commonly preyed upon by the pink- 

 ish larvae of Lestodiplosis, and it is probable that Itonida pug- 

 ion i s Felt has similar habits. The larger predaceous maggots of 

 Lonchaea polita Loew and a species of Aledetrus were 

 commonly found in the vicinity of ]\Iiastor colonies and were not 

 infrequently the only available evidence of the earlier presence of 

 midge larvae. Pseudotephritis vau Say was repeatedly 

 reared from bark infested by Miastor larvae. In some instances the 

 Pseudotephritis larvae occurred in clusters. These larvae may be 

 predaceous enemies of the smaller ]Miastors. 



