288 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



conditions makes it possible to avoid the tedious and expensive 

 methods necessary with Blepharipa and Crossocosmia, to which would 

 be added the painful and disagreeable task of a close examination of 

 the masses of brown-tail moth cocoons in order to secure all of the 

 puparia of this species so that they might be buried in earth ancl 

 kept moist during the winter. 



As to the physiological reasons for the ability of this species and 

 those of the same habit to withstand exposure, no more can be said 

 than that if the advanced stage of development of the hibernating 

 nymphs of the parasites of the first class renders them susceptible to 

 drying influences, than contrariwise, on account of the undeveloped 

 state and slight activity of the internal organs of these forms, they do 

 not require so much moisture nor do they give up their moisture 

 content so readily. Although they can thus pupate and hibernate 

 out of the soil, some of them, as we have observed in the case of 

 Varichceta alclrichii Towns., habitually descend into the earth to 

 pupate if they can easily do so. It is, of course, impossible to deny 

 that long exposure to very dry conditions may have a detrimental 

 effect upon certain individuals, but it seems more likely that they 

 pupate in the soil in order to avoid the parasitic and predatory 

 enemies to which they would be exposed for so long a time, did they 

 remain unprotected upon the surface of the earth. 



The parasites of the second sub-division pupate in various ways 

 which seem to be determined more by the condition of the host' and 

 the individuality of the parasite than by the factors which influence 

 the pupation of the parasites of the first class. Some of them, among 

 which may be mentioned Eudoromyia magnicornis Zett., and Zygo- 

 bothria nicUcola Towns., pupate within the empty skin of the host 

 which tightly encases the puparium. In this situation they are no 

 doubt to a certain extent protected from secondary parasites. The 

 wall of the puparia of these species is, so far as we have observed, 

 quite thin and delicate, the skin of the host serving the same purpose 

 as does the thicker wall of the puparia of the species which pupate 

 freely. There are also other species, such as Tricholyga grandis Zett., 

 Tachina tnella W., and Euphorocera claripennis Macq., which pupate 

 loosely within either the empty host skin or the pupa. These fre- 

 quently occur to the number of three or four within a single host 

 whereas niagnicornis and nidicolu are nearly always solitary. More- 

 over they do not always pupate in the manner above described but 

 sometimes emerge from the body of the prepupal caterpillars or from 

 the pupa, pupating either within the cocoon of the host if there is 

 such, or leaving it and dropping to the ground. The wall of the 



