202 THE CANADIAN ENTOMOLOGIST. 



large and bears two very large and prominent compound eyes. These 

 eyes, which consist of many thousand facettes each, are so large that they 

 meet on the upper surface of the head. This great power of vision is 

 still increased by three simple eyes, or ocelli, situate on the upper surface 

 of the head. From the front part of the head project two short, tapering 

 antennae. The mouth occupies the front under surface of the head, and is a 

 most formidable structure. The upper lip is broad, and conceals very 

 powerful toothed organs, called mandibles; other organs of the mouth are 

 also armed with strong teeth which enable the creature to satisfy its carniv- 

 orous desires. The most remarkable portion of the mouth, however, is 

 the lower lip, a large, flat, lobed organ, closing the mouth from the under 

 side, and which may be projected forward to a comparatively great 

 distance when attacking other insects. 



The thorax, or middle portion of the body, is three or four times as 

 long as the head, and very much greater in diameter. It resembles the 

 head in colour, being a medium chocolate shade, and is sparsely clothed 

 with very short hairs of the same hue. 



The abdomen, or posterior part of Z. trimaculata tapers very gradually 

 to the end, and is much smaller in diameter than the thorax, but more 

 than twice its length. The colour is slightly paler, and is relieved by a 

 line of pale yellowish blotches along each side, which gradually become 

 smaller in size toward the end of the body. The upper surface is arched, 

 while the under is flattened. 



The legs are six in number, and are attached three to each side of the 

 lower surface of the thorax. 



The wings, which are four in number, are attached two to each side of 

 the upper surface of the thorax, and are about one and a quarter inches 

 long, and three eighths to nearly half an inch in breadth ; the front ones 

 being slightly the narrowest. The substance of the wings is a very deli- 

 cate net-work covered by a thin transparent membrane having a shining 

 surface. From the place of attachment of each wing there proceeds a 

 narrow elongated patch of a deep brown colour, while from about the 

 middle of the wings there is a large irregular patch of the same colour, 

 which extends completely across. The structure of the wings combines 

 great strength with lightness, thereby enabling the insect to fly with very 

 great rapidity. Their shining surface, transparency, and brilliant colouring 

 in this and other members of the same order, combine to give them a 



