A BEETLE 



INSECTA 



A COLEOPTEROUS INSECT. A LARGE BEETLE 



Compare the animal with the wasp. We notice, in the first 

 place, the heavier and clumsier body and the smaller head. 

 The animal is evidently much less active and also less intel- 

 ligent than the wasp. We notice, also, that the wings lie close 

 to the body instead of being raised above it. The forward or 

 mesothoracic wings are hard and thick ; they are not used for 

 flight, but cover the metathoracic pair and the hinder part of 

 the body and are called the wing-covers or elytra. They form, 

 thus, an additional protection to the back. The entire body of 

 most beetles, in fact, has a thicker cuticula and, consequently, 

 a more effective external covering than that of the wasp. 

 This feature may be correlated with the smaller intelligence of 

 the animal. Opening the elytra, we notice beneath them the 

 membranous metathoracic wings with which the animal flies ; 

 we notice also that they are folded transversely as well as longi- 

 tudinally. These wings are wanting in some of the running 

 beetles, where the wing-covers are sometimes fused. Note the 

 scutellum, the small triangular plate, between the base of the 

 wing-covers. Find the eyes and note their small size. Are 

 ocelli present? Find the antennae; in some beetles they are 

 often concealed beneath the sides of the head. 



Exercise l. Draw an outline of the dorsal aspect of the 



beetle on a scale of 4 or 5. First, however, spread 



and pin the right wing-cover and wing. Number the 



thoracic and abdominal segments and label all the parts 

 observed. 



