December, '16] hungerford: sciara imaggots injuriou.s 539 



appearance of the plants to some physiological condition of the soil or 

 surroundings. 



The meager literature dealing with Mycetophilid depredations was 

 scanned, and recommendations for control were made accordingly. 

 It was very shortly discovered that the remedial measures given were 

 decidedly ineffective when applied against these maggots, and, after 

 running the gamut of the "suggested controls," we were compelled to 

 admit to our friends that in the present state of our knowledge, we 

 knew no satisfactory means of control. 



To prevent any future embarrassment of the kind, the writer began 

 a series of experiments, to determine the cause for the infestations, the 

 nature of the injury, if any, the life-history and the control. 



Literature 



These insects have received but little attention from the economic 

 entomologists, if we may judge from the literature. Most of the 

 references are mere reports of their occurrence or injury. The grega- 

 rious migratory habit of some species has been reported from many 

 quarters. Fifteen out of some thirty-five references relating to the 

 biology of members of this family are devoted to noting this phenom- 

 enon. While the life-histories of but few have been reported, Beling 

 (l),i Bezzi (2), Girard (9), Pastejrik (17), in articles not accessible 

 to us, have dealt with the biology of various species of the genus. - 

 Chittenden (5) gives the description of the larva and pupal stages, but 

 the eggs were unknown to him and the length of the various stages not 

 mentioned. Coquillett (6) describes pupation of Sciara tritici as 

 occurring in an oval cell lined with a few silken threads. He also 

 noted the eggs of this species as being scattered on the ground or 

 deposited in clusters of twenty or more. He describes the eggs as oval, 

 polished, white, and measuring about 1/10 of a millimeter in length. 

 The length of the various stages was not known. 



' See Bibliography. 



^ Since writing the above 1 have had the opportunity to review these papers in the 

 libraries of Cornell University. BeUng (1) gathered the maggots of twenty-four 

 species from their breeding places in decaying wood, under fallen leaves in cow dung, 

 etc. He describes the maggots and pupip, giving in most cases the length of the 

 pupal stage. In three instances he mentions the eggs but does not state the length 

 of the incubation period. Bezzi (2) describes the eggs of S. annlis as white, oval, 

 twice longer than broad, and with such fine punctures that they appear smooth to 

 the naked eye. The females lay from 200 to 240 eggs in more or less numerous 

 clumps. The incubation period is given as seven days, the larval stage a little over 

 a month and the pupal stage a week. — This article in Itahan is perhaps the most com- 

 plete accoimt of the life history of any Sciara. 



