186 Zoology of Colorado 



which attack our crops. Not only are there many forms differing 

 greatly in appearance, but in certain genera we have series of very 

 closely allied species, requiring anatomical studies for proper 

 discrimination. Thus in the genus Peleteria we had listed three 

 supposedly well known species. Mr. C. H. Curran, making a 

 critical revision, found that none of these occured in Colorado, 

 but instead we had no less than thirteen new species. One of 

 these, P. campestris Curran, has been taken on the campus of the 

 University of Colorado (Ada Kneale). A previously known 

 species, P. iterans Walker, was taken at Ward (W. P. Cockerell). 

 These were determined by Mr. Curran. A pretty species, easily 

 recognized by the abdomen having the basal half or more pale 

 yellow, the apical portion black, is Xanthopalpus bicolor Williston. 

 It occurs on flowers of Rudbechia laciniata in Peaceful Valley, and 

 was found in the Hudsonian Zone on Long's Peak trail. 



The related Sarcophagidae have a peculiarly marked abdomen, 

 with a sort of checker-board effect, and the tip is often red. We 

 have sixteen species belonging to the genus Sarcophaga. S. 

 eleodis Aldrich is parasitic on the slow moving evil smelling beetles 

 of the genus Rhodes. Several species are parasitic on grasshoppers. 



The limits of the family Muscidae are subject to dispute, but 

 as generally understood we may include the following common 

 flies : 



Pollenia rudis Fabricius, which is parasitic in the larva state 

 on earthworms. The flies collect in houses, and sometimes be- 

 come so abundant as to cause great inconvenience. (See 

 Nature, Feb. 9, 1924, p. 193.) It is known by the loose yellow 

 pile on thorax. 



Calliphora erythrocephala Meigen, the common bluebottle 



fly. 



Lucilia caesar Linnaeus, the greenbottle fly, smaller than 

 the last. There are other related forms, such as Protophormia 

 terrae-novae Desvoidy, which occurs on the University of Colo- 

 rado campus (Phyllis Burk) and up to timber line on the Long's 

 Peak trail. It is a much darker insect than the greenbottle. 

 Cryptolucilia caesarion Meigen is a common green fly very like 

 the greenbottle, but metallic between the eyes, and with a prom- 

 inent bristle on the inner surface of each middle tibia. 



Musca domestica Linnaeus, the common house fly, much re- 



