307 



attacking cattle the most vulnerable portions are best calculated to 

 yield the best results to these small insects with their rather short 

 mouth-parts, and that the most vulnerable parts are those near the 

 upper extremities of the legs. I have found in the case of Sitnuliidcc, 

 or black flies, that while they may be found upon almost any part of 

 the body of a cow or horse they are more often found on the under 

 surface of the body close to the leg or, in the case of the horse particu- 

 larly, inside the ear — the most vulnerable spots. 



The blood-sucking species of Ceratopogonince are mostly crepuscu- 

 lar in habit, and in most cases I found that during May and June the 

 greatest numbers occurred after five o'clock in the afternoon, continu- 

 ing active until 8 p. m. at least, this being the latest hour that it was 

 possible for me to make observations. From experience at other times 

 and in other localities I know, however, that the insects bite as late as 

 lo p. m. The earliest hour at which I found guttipcnnis biting was i 

 p. m. On this occasion the sun was shining, but an hour or so later a 

 short thunder storm occurred, the weather conditions very probably 

 being responsible for the utiusual occurrence of the species. 



When in the act of biting it was not always easy to capture this 

 species in a cyanide vial, as the insects were very readily disturbed, 

 which is not the case with the smaller species, higuttatiis and san- 

 guisugiis. 



May 9, only one specimen was taken; on May 15 but two; while 

 on May 30, thirty-five specimens were collected, all in the act of biting. 

 On the first two dates higuttatiis was the commonest species. On vari- 

 ous dates in June and July guttipennis was found to occur commonly, 

 but no large collection was made. 



In my paper previously referred to I stated that the early stages of 

 guttipcnnis were undescribed. Lest there should be any misunder- 

 standing on this point it may be pertinent to indicate that meaningless 

 figures of the larva and pupa accompanied by absolutely inadequate 

 descriptions are given by Pratt in his paper referred to on a previous 

 page. 



CUUCOIDES STEI.I.1FER Coquillett 



Two specimens of this species were taken in the act of biting the 

 writer, August 8, 191 5, on bank of Sangamon River, near White 

 Heath. 



CUEICOIDES SANGUISUCUS Coquillctt 



This species is found commonly in Urbana, large numl)ers of both 

 sexes being taken on windows of stores in the city after the lights arc 

 turned on. I have also taken many specimens on the inner side of win- 



