50 HOUSEHOLD INSECTS 



one just discussed and is more brilliant in color, some- 

 times bluish and sometimes greenish. It is common in 

 this country and in Europe. It frequently enters houses, 

 especially just before rain-storms. It breeds in carrion, 

 in sores on living animals and in the excrement of man and 

 other animals. The larvae are very similar to those of 

 the first blow-fly discussed except that they are smaller. 



THE MOTH-FLIES 



Psychoda mirnda 



There are often found upon window panes certain 

 tiny flies with broad wings densely clothed with hairs. 

 In appearance they resemble very small moths and are, 

 therefore, known as moth-flies. They belong to the family 

 Psychodidse and may be distinguished from all other flies 

 by their moth-like appearance. The larvae of some of 

 these flies live in cow-dung, others in decaying vegetation, 

 while some live in water, especially sewage water or 

 drain water from kitchens. We have seen hundreds of 

 these moth-flies among the weeds overhanging a ditch 

 carrying the drainage water from a kitchen. We have also 

 seen them in abundance along ditches carrying sewage 

 water from houses. In the first-mentioned instance they 

 were always present on the window panes of the kitchen, 

 readily passing through the ordinary wire screen. Judg- 

 ing them from the places in which they breed, we would 

 consider them unwelcome guests in our houses. 



Almost nothing is known of the life history of the North 

 American species. Kellogg found the larvae of one species 

 of moth-fly, Pericoma calif ornica, in a stream in California. 

 He found the larva were slug-like, about one-tenth of 



