Insects 187 



duced in numbers since the automobile came in, as it breeds 

 principally in horse manure. 



Stomoxys calcitrant Linnaeus, very like a house fly, but with 

 a proboscis adapted for sucking blood. It is often called the 

 Stable Fly, and has been suspected of carrying the organisms of 

 disease. 



Haematobia serrata Desvoidy, the Horn Fly, smaller than 

 the house fly, and found on cattle, causing them annoyance by 

 their bites. It has been noticed at the lower end of Boulder 

 Canyon. 



In the shales at Florissant, we find no Muscidae, Sarcopha- 

 gidae, or Tachinidae, but instead several fossil species of Glossi- 

 nidae, the tsetse flies, now existing in Africa. 



There are numerous families of mostly small flies related to 

 the Muscidae, but we cannot describe them here. Eurosta bige- 

 loviae Cockerell, in the family Trypetidae, is a fly with prettily 

 marked wings, which breeds in rounded white galls on stems of 

 Chrysothamnus. 



Drosophila mclanogaster Meigen, of the Drosophilidae, is the 

 little red-eyed fruit fly which in the hands of Professor T. H. 

 Morgan and his associates has revolutionized the science of 

 heredity, developing the Mendelian theory in ways previously 

 unimagined. It may occasionally be found on windows in 

 Boulder and elsewhere. The Wheat-stem Maggot, Meromyza 

 americana Fitch, of the Chloropidae, is injurious to wheat. 



The curious parasitic fly Trichobius corynorhini Cockerell 

 (Family Hippoboscidae) is found on the Big-eared Bat (Corynor- 

 hinus). It was first found in the Great Sphinx Mine, Boulder 

 County. 



HYMENOPTERA 



The great group of ants, bees, wasps, sawflies, etc., richly 

 represented in Colorado. Opinions differ as to the number of 

 families to be recognized, but in recent years the tendency has 

 been to divide them more and more. In Comstock's Intro- 

 duction to Entomology (1924) some of the currently recognized 

 families of bees and wasps are united, but the result seems to 

 me to be confusing. The arrangement given by Essig, in his 



