830 



JOHN B. SMITH. 



Fig. lo. Galea of mos 

 quito. 



add none of my own, save that of the tip of the galea. This differs 

 somewhat from Dr. Dimraock's figures of the same structure ; but the 

 species are different, and I have found that no two of the five species 

 examined agree, nor do any agree with Dr. Dimmock's species. It 

 is readily seen that while we have here in essentials the chitinous 

 structure of siTmdmm, yet we get a tendency in the 

 terminal joint to form a mere chitinous cap, a 

 breaking up of the chitine into fragments and a 

 filmy covering over the inner face — the rudimen- 

 tary label la. 



At this point we drop the piercing flies, and now 

 we find in point of development a steady loss in 

 the piercing organs, and as regular a gain in the 

 galea. It is worth noting, too, that while the ful- 

 crum in the piercers is not developed where the 

 mouth parts are much divided, it becomes promi- 

 nent as the maxillary development becomes weak. 

 In Calex there is a very pretty little fulcrum, much like that of the 

 Leptid, hereinafter figured. In Stomoxys there is a very decided 

 development. It is a suggestive fact that when the mentum disap- 

 pears, the development of the fulcrum begins. 



Bombyllm sp., m \vh\ch the mouth parts are elongated, forms a 

 good subject for the next figure. 



This is one of the species in which the proboscis is carried straight 

 forward, and the fiexion is so strong that it is not easily overcome. 



The fulcrum of the fig- 

 ure is therefore seen 

 flexed upon the labium, 

 to which it is articulated 

 at its base. The ligula 

 is quite closely united 

 with the paraglossse, and 

 is so shown in the figure. 

 '^I'he lacinia are flattened 

 strips arising at the sides 

 of the labium and partly 

 enveloping it. The pal- 

 piter is a fine seta, shorter than the lacinia or labium, and with a 

 basal extension above the insertion of palpi. This is an interesting 

 fact, as a beginning in the peculiar change undergone by this part. 



Fig. II. Mouth psLTts of Bo»t/iy/ius sp. 



