ou blood at frequent intervals lived for 17 days. Tlie length of 

 the egg stage varies — from one to four days. Temperature and 

 humidity, as well as the lengtli of time the eggs are retained by 

 the female, appear to affect the rapidity of incubation. The 

 larval period varies from about eleven to over thirty days ; in cold 

 weather this stage would probably be much longer. The mini- 

 mum developmental period from egg to adult is from 2o-32 days, 

 according to the character of food supplied. The pupal stage 

 varies from six to about twenty days. 



No records were taken of hibernation but an examination of 

 stacks in the middle of December shoAved an abundance of larvae 

 in various stages of growth and many pupae ; active adults too 

 have been found in December. The insect is usually much more 

 numerous during the late summer and early autumn. The 

 unusual plague in Texas in August and September was due to a 

 large crop of grain, incidentally producing a great number of 

 straw stacks, combined with the unusually heavy rains in early 

 August. Many stacks were recently thrashed, and, being loosely 

 piled, absorbed the rains as they fell. In a few days the entire 

 mass became rotten and heated and thus afforded precisely the 

 conditions most suitable for the reproduction of Stomoxijs. ^ 



The larvae are able to withstand a great amount of moisture, 

 often feeding on straw when it is saturated with water, and in the 

 older larvae pupation is often hastened as a result of exposure to 

 extremes of moisture and temperature. The drying out of straw 

 stacks to a depth of six or eiglit inches largely prevents the 

 deposition of eggs in these situations, the stacks under these con- 

 ditions being unattractive to the adult fly. 



Parasites have been found in numerous pupae of Stomo.vijs, 

 two small Hymenoptera of the family Pteromalidae having 

 been bred in large numbers. One of these is SpaUngia inuscae 

 and the other is an undetermined species of a different genus. 

 Out of 2,500 pupae examined over 40 per cent, were parasitised by 

 these two species. Experiments show that parasitism always 

 takes place in the pupal stage. Both of the parasites have been 

 found to attack the pupa of the house-fly and of the horn Hy 

 {Uaematohia sermta), as well as other Muscid pupae. 



During the outbreak of this fly predaceous insects were present 

 in large numbers. Adults of StomcKvys were captured by many 

 species of Asilidae, which were present m great numbers around 

 straw stacks. Several species of spiders were seen to capture and 

 devour the adults : while two or three species of mites were found 

 to be enemies of the immature and adult stages. In manure and 

 straw Histerid beetles were among the more important predators. 



Straw stacks should not be allowed to rot, thus forming_ favour- 

 able breeding places for Stomo^vjjs. All straw not required tor 

 winter feed for cattle should be destroyed by burning, or it 

 should be scattered over the land soon after threshing and 

 ploughed under subsequently. The use of poisons m quantities 

 suflicient to permeate the stacks and kill the larvae would be very 

 dangerous to stock. Whenever manure is mixed with straw it 

 may be suspected of forming a breeding place for Stomo.vys. The 

 thorough scattering of manure at regular intervals, as is recom- 

 mended for the control of the house-fly, is effective m stopping 



