42 



GUIDE TO INSECTS. 



Table- Drawings and specimens of Triclio elect es latus (1501, fig. 42) 



case 37. found on dogs, Menopon pallidum found on fowls, and other species 

 are exhibited. 



Like most parasites they are difficult to locate satisfactorily in 



Fig. 42. 



Trichodectes latus, from dog ; enlarged thirty-six times. 



any natural system, but they appear to be most nearly allied to the 

 Orfhoptera. 



Order LEPIDOPTERA. 



Table- The insects of this Order are popularly known as Butterflies and 



case 38. Moths. 



They undergo a complete metamorphosis. The larva is popularly 

 called a caterpillar; the pupa a chrysalis. The perfect insect has 

 the head free. The thorax is compact. The prothorax very small ; 

 the mesothorax very large. The wings are very variable, clothed 

 (as well as the body) with scales. The mouth parts (Fig. 43) are 

 imperfectly developed, except the maxillge which (except in a few 

 cases) are greatly prolonged and united by their edges to form a 

 proboscis or tube (through which moisture can be drawn into the 

 mouth), coiled like a watch-spring when at rest. The labial palpi 

 are well developed, usually standing up in front of the head, 

 sometimes of great length. The maxillary palpi are very small or 

 absent. 



