258 HALF-AN-HOUR AT 



hard and dark-coloured, and within this puparium the real pupa is 

 found, and from which the fly escapes by scaling off the notched 

 extremity of the case. Although these insects are furnished with 

 a pair of remarkable ovaries, their progeny consists but of a single 

 pupa, after the exclusion of which the abdomen becomes shri- 

 velled and contracted " {Joe. cii., p. 584). 



The "curious appendages at apex of thorax," referred toby 

 Dr. Rowe (p. 260), demand attentive consideration : — " They have 

 neither wings nor balancers," says the learned author we have so 

 frequently quoted, " but the intermediate legs are connected at 

 the base with a pair of strong, comb-like organs, which are the 

 probable representatives of wings." And such turns out to be the 

 case ! The scales to which these strong, abbreviated bristles are 

 attached are riidi??ientary wings! You will hardly wonder after 

 this to learn that rudimentary balancers are also present, or that 

 " Mr. McLeay has shown me" (Professor Westwood) "species 

 from the West Indies possessing short wings." 



When all the forms we can obtain have been round the 

 Society, and the facts they present come to be grouped in series, 

 you will be perhaps better able than now to appreciate the delight 

 with which I studied these parasites of Flying Fox. I was eagerly 

 wishful to see specimens, and they came in answer to the unut- 

 tered wish. The " quaint zone of processes " is simply an 

 excessive development of strong hairs present at the free edge of 

 the first abdominal segment in ordinary flies. Another very 

 remarkable point is the division of the femur into two portions, of 

 the tibia into three, of the basal joint of the tarsus into numerous 

 articulations (twenty-five). This " vegetative repetition," as Pro- 

 fessor Owen has aptly termed similar conditions, is paralleled in 

 Phalangiuni, the long-limbed autumnal spider, or "Harvestman." 

 The form of the claws is, as the contributor has well expressed it, 

 wonderfully adapted for clinging to its victim. In thinking over 

 the claws of other clinging creatures by way of instituting a com- 

 parison, it occurred to me, " Why, that's wonderfully like the 

 claws of sloths, that spend all their lives hanging to the branches 

 of trees," and the claws of the flea, that hang on to our skin so 

 vivaciously, and the claws of Melophagus, and so on. But it 

 would take a long paper to describe all worthy of note in this 

 interesting creature. 



Melophag^us ovinus, Sheep-Tick (PI. XVII., Fig. 6) will be fully 

 described in the explanation of that Plate. 



Wing of House-Fly is from Mima domestica, the smaller 

 house-fly. It looks like the work of a beginner, who deserves 

 genuine praise for giving his attention to the natural objects 

 whereby he is surrounded. If we keep that steadily in view, we 



