Dec, 1913] Townsend: Notes on Exoristid^. 301 



NOTES ON EXORISTID^ (TACHINID^ AUCTT.) 

 AND ALLIES. 



By Charles H. T. Townsend, 

 Lima, Peru. 



The writer has observed with much satisfaction the advent of sev- 

 eral new North American workers in this field within the past five 

 years, and trusts not only that their number will be trebled or quad- 

 rupled within the next five years, but that all of these new students 

 will publish conscientious descriptions of as many new forms as it 

 may be possible for them to find among these flies. Notwithstanding 

 the numerous forms already described, there is a host of geilera and 

 species still awaiting characterization. If the student is so fortunate 

 as to be a competent artist himself, he should present drawings of the 

 new forms characterized. Mr. W. R. Walton's work in this respect 

 is much to be commended. His plates are models of accuracy and 

 constitute the first thoroughly competent drawings of Muscoidea to 

 appear for almost a quarter of a century — since the eleven quarto 

 plates by Brauer & von Bergenstamm published in 1889, with which 

 they compare very favorably (except that the proboscis and palpi 

 should always be drawn with the head if they are sufficiently exserted 

 in the original). Students of Muscoidea who can produce drawings 

 of this class are much to be desired, for it must be recognized that no 

 drawings in this superfamily can approach accuracy unless made by 

 a specialist in the group. The drawings made by Dr. Williston five 

 years ago for the third edition of his " Manual " are excellent and 

 deserve much credit, but they are unfortunately too much reduced and 

 in consequence do not always show details accurately. Enlarged pho- 

 tographs properly made will be found extremely serviceable, but so 

 far competent drawings are found to show details far better. It may 

 be possible in the future to develop insect photography sufficiently 

 to show all external muscoid characters clearly, but until that day 

 arrives drawings must take first place. 



Aside from drawings, descriptions need to be carefully made, not 

 omitting from generic or specific diagnoses mention of any characters 

 that may help to place the form in hand. Cases to be noted are omis- 

 sion of ocellar bristles present or absent, comparative length of an- 



