(115) 



356. 0. GORDON HEWITT. 



of the thorax being blackish with three black longitudinal 

 stripes; the frontal region is very narrow; the abdomen is 

 grey with a .dark median stripe. The average length of the 

 body is 5 mm. 



In the summer they are common and may be found in the 

 neighbourhood of manure. The eggs are laid in this substance, 

 especially in horse-manure. The larvae have also been 

 found feeding on the roots of various cultivated cruciferous 

 plants, from which the insect has derived the name " root- 

 maggot." The eggs hatch out from eighteen to thirty-six 

 hours after deposition. The first larval stadium lasts twenty- 

 four hours, the second forty-eight hours, and five days later 

 the larva changes into a pupa, the whole larval life occupy- 

 ing about eight days. The pupal stage lasts ten days, so that 

 in warm weather the development may be completed in nine- 

 teen to twenty days. The full-grown larvae measure 8 mm. 

 in length, and may be distinguished by the tubercles sur- 

 rounding the caudal extremity. In this species there are six 

 pairs of spinous tubercles surrounding the posterior end and 

 a seventh pair is situated on the ventral surface posterior to 

 the anus. The tubercles of the sixth pair, counting from the 

 dorsal side, are smaller than the rest and are bifid. The 

 arrangement of the tubercles can be seen in fig. 2. The 

 anterior spiracular processes (fig. 3) are yellow in colour and 

 have thirteen lobes. 



(6) Stomoxys calci trans Linn. 



The species is common, especially in the country from 

 July to October, and during these months it may be often 

 found in houses, although Harness observations (1908) 

 appear to indicate that the presence of cowsheds, in which 

 they occur in large numbers, does not affect their numbers 

 in houses. I have found S. calcitrans in large numbers 

 in the windows of a country house in March and April, 

 and it may be found frequently out of doors on a sunny 

 dav in May, and throughout the ensuing summer months. 

 It is normally an outdoor insect, but appears to seek the shelter 



