84 Annals Entomological Society of America [Vol. VIII, 
Vickery at Brownsville, Tex.; from Chorizagrotis agrestis by 
Kelly at Wellington, Kans.; and from Paragrotis ridingsiana 
by Doten at Austin, Nev. (Unpublished records). Tessellata 
is so closely allied that it undoubtedly attacks Lepidoptera, 
though not yet reared. 
Omitting the less common species, there are a few facts 
to be emphasized in the ones above discussed. 
First, among twenty-four commonest North American 
Tachinidae, twelve are known to parasitize Lepidoptera, three 
each the Coleoptera and Hemiptera, one each the Hymenoptera 
and Orthoptera; while in four the larval habits are unknown, 
only one of these last however probably attacking the Lepidop- 
tera. 
Second, that several of these species are probably single- 
brooded. Parasitism seems in these cases to have restrained 
within narrow limits the ordinary, primitive exuberance and 
rapidity of Muscid development. The economic importance 
also of the species is materially affected by this limitation. 
Third, that the natural history of these species is mostly 
unknown or at least unpublished. While some progress has 
been made in studying the internal anatomy of the females and 
making out the stage of advancement at which the young are 
deposited, there is a great lack so far of field work on the re- 
production, as well as of dissection of infested hosts to ascertain 
the mode of life of the larva. There should be more workers 
in this field. Merely to find and record a fly in the breeding 
cage where a cutworm moth was due is but a small contribution, 
though a useful one, to the biology of the fly. Mr. Walton's 
interesting published observation on larviposition in Cheto- 
phleps setosa Coq., the cucumber beetle parasite,* illustrate 
the sort of beginnings we must have in order to handle the sub- 
ject properly. Hence in conclusion I cannot too strongly 
commend to the rising generation as a research subject the 
biology of parasitic diptera, in which there are many discoveries 
to be made, of both scientific and economic importance, and 
of general interest as well. 
My acknowledgments are due to Dr. Webster for permis- 
sion to use unpublished records, and to Mr. Walton for gener- 
ously furnishing them in advance of his forth-coming new host 
index of Tachinide. : 
*Mentioned in his article as Neocelatoria ferox. 
