1919] Traver — Lejndopterous Genus Depressaria 75 



Of these two hundred and forty-nine species, the hfe-histories of 

 ninety-four are recorded. H. T. Stainton has probably given us the 

 most material, in a compact form but very comprehensive, in his 

 Natural History of the Tinenia. In volume six of this work, he 

 treats of the life-histories of twenty-four species, while in volume 

 twelve he adds twelve more to the list. Chretien, likewise, among 

 recent entomologists, seems to have devoted much time to life- 

 history work among the smaller forms, and he has given us much 

 valuable data of this sort for the genus Depressaria. Besides the 

 thirty-six species treated by Stainton, fifty-eight others have been 

 reared or otherwise studied by other workers, so that their habits 

 are known. For one hundred and eighteen of the remaining species 

 merely distribution and description, usually of adult alone, but 

 occasionally of larva and pupa also, have been given. Complete 

 references for thirty-three of these species were not available. 

 The references to the rest of the species include likewise some men- 

 tion of the food plant of the larva. That is to say, for 53 per cent, 

 of the genus, something of the life-history and habits is known. 

 Since an ecological study of a group depends mainly on such material 

 as this, it is clearly impossible to give more than an estimate of that 

 group, when so much remains to be determined. The tables given 

 are, therefore, in no sense complete, but merely an arrangement of 

 such biologic knowledge of the group as has been verified. 



Ten of the species are known to be gregarious in their larval 

 habits, a number of larvae living together on the same leaf or in the 

 same umbel. Twenty-two, however, are recorded as being 

 solitary in the larval state, while no mention is made of the social 

 habits of any of the others. 



Of the seasonal distribution, no very definite facts could be 

 learned. Several are known to pass the winter as images, a few as 

 larvae, and others in the egg stage. Mention is made by Chretien of 

 one species, D. halophilella, which "lives during the winter in the 

 interior of the stems, the shoots and the pulpy leaves of CritJiinum 

 maritimus." It seems to be generally accepted that the genus is 

 single-brooded and that the eggs do not hatch till rather late in the 

 spring. In the case of those passing the winter in the imago form, 

 it is several times noted that the adult insect is rarely seen in the 

 fall, but more commonly in the spring after its hibernation^ 



Stainton writes of the adult insects: "The perfect insects of the 



