THE CH A:\lELEON-FLy. 611 



' If the mornings or evenings are frosty or damp, the insects 

 are dull and torpid, and may easily be taken with the hand ; 

 but if the weather be hot and dry, they are lively and saucy,* 

 and fly away as the captor approaches. They are, however, so 

 silly, that often, wlien they seem to be flying away, they rise 

 up in the air, make a short gyration, and descend, with a 

 sudden dart, at his very feet. 



*" The time of the appearance of the perfect fly varies 

 according as the season has been warm and Cvy or cold and 

 damp. In the course of the four years that I watched for 

 them, their first appearance varied from the eighth of Augiist 

 to the fifth of Septem]>er, and their disappearance from 

 the fifth to the thirtieth of September. The process of 

 transformation from the larva to the fly continued, in the 

 entire community of them, from twenty-one to twenty-five 

 days.' 



The pupa of this insect is shown at Fig. 6. Fig. a repre- 

 sents a magnified profile view of the head of the perfect insect, 

 and Fig. d is the front view of the mouth. 



We now come to the second division of the Cephalota, 

 namely the Brachocera, or Short-horned Diptera. They are 

 divided into smaller groups, or Stirpes, as jNlr. Westwood 

 calls them. The first of them is the Notacantha, or Thorn- 

 backs, in which the antennae are apparently composed of only 

 three joints (of which the last is seen, when examined by a 

 lens, to be articulated), and the proboscis seldom contains 

 more than two lancets. The pupa is enclosed in the skin of 

 the larva, which, however, retains its previous shape instead of 

 being formed into an oval cocoon, as is the case with the com- 

 mon flies and bluebottles. We can only take one example of 

 this group, the Forked Chameleon Fly {^Strationiys furcata\ 

 which is represented on Woodcut LXXI. Fig. 3. In this 

 genus the proboscis is very short, and the basal joint of the 

 antennae is much longer than the second. The third joint is 

 apparently very long, but the microscope shows that it is 

 composed of several joints fused together, as may be seen by 

 reference to Fig. h. 



JNlost of the insects belonging to this family are beautifully 

 coloured, and many of them shine with metallic tints, mostly 



B B 2 



