FLIES FOUND IN HOUSES 23 



jowls reddish %mth black hairs. The upper portion of the antenna dark grey, the 



lower joint and arista black. The upper portion of the arista is feathered, but 



the terminal one-fourth bare. 

 Thorax. Bluish grey, with indistinct darker blue longitudinal markings, and covered 



with numerous short black hairs, and longer black bristles. The longest of these 



are situated on the scutellum (see PI. I, fig. i). 

 Wings. Clear; squama opaque, yellowish white, and covers the halteres which are 



rather small. 

 Legs. Black, and covered with hairs and bristles. Pulvilli prominent. 

 Abdomen. Paler blue than thorax with darker blue, indistinct markings especially 



on second and third segments. The anterior three-quarters of each segment is 



covered by white pubescence. 



According to Hermes (1911), this fly is not greatly attracted 

 to light. It frequently enters houses, and is apt to lay its eggs 

 on cold meat and other substances and to walk over any foods 

 which may be exposed, stopping at intervals to suck the fluid 

 parts. Outside the house it frequents decaying animal and 

 vegetable matter and excrement on which it feeds and lays its 

 eggs, and often visits fruit and meat exposed for sale. .According 

 to Porchinsky the female fly lays from 450 to 600 eggs. 



The egg measures i'4 to i "5 mm. in length, "and has the form of an elongated 

 ellipsoid, which is smaller at its anterior and broader at its posterior end. Its long 

 axis is slightly curved, so that its ventral surface is convex and its dorsal surface flat, 

 or even slightly concave" (Lowne, 1895, p. 678). 



The larva when full-grown measures 18 mm. and "is a soft-skinned, cylindrical, 

 wedge shaped worm, gradually increasing in diameter from before backwards, and 

 truncated behind obliquely, so that the posterior extremity exhibits a concave surface, 

 which looks upwards and backwards, within which the great posterior spiracles are 

 situated" (Lowne, p. 32). There are twelve well marked visible segments, the 

 fourth to the tenth showing foot-pads beneath. "Each segment has a thickened 

 anterior border, covered by short recurved spines and sensory papillse. The spines 

 apparently prevent a retrograde movement in burrowing." The posterior end is 

 surrounded by six pairs of tubercles, and a seventh pair is situated on the ventral 

 surface posterior to the anus. PI. II, fig. 4. Before pupating the larva ceases to 

 feed, generally seeks a place of safety, and becomes languid and motionless. Before 

 resting they often burrow a short distance into the ground. The pupce are barrel 

 shaped and dull red in colour. 



According to Hewitt (19 12, p. 48) the eggs hatch out " from 

 eight to twenty hours after deposition " ; the larval life, composed 

 of three stages, the first and second lasting twenty-four hours 

 and the third six days, is passed in seven and a half to eight 

 days, and the pupal stage lasts fourteen days. 



