INTRODUCTION TO ENTOMOLOGY. 



not an uncommon occur Bummer-time to see 



huii' them flying about a single street-lamp. 



They are very fragile insc 

 with large delicate fore wings. 

 with the hind wings much smaller 

 or \\anting. and with the abdo- 

 men furnished at its caudal end 

 with either two or three many- 

 jointed, thread-like appendages 

 i Fig-;. C>4 and fytf). 



The body is smooth, not 



FIG. 64. May-fly. FIG. 64**. CV**/x. 



clothed with scales or hairs. The head is free, with atrophied 

 mouth-parts, and inconspicuous antenna.-. These- are composed 

 of two short stout segments succeeded by a slender many-jointed 



lie. Tlie thorax is robust, with the mesothorax predomi- 

 nant. The great development of this segment is correlated 

 with the lai of the fore wings. The abdomen is long, 



soft, and composed of ten segments. In the male there is a pair 

 of cla-ping organs placed ventrally at the extremity of the ninth 

 ment : t usually two-, three-, or four-jointed, and arc- termed 



the forceps-limbs. Just behind the forceps-limbs are the paired 

 ternal .sexual organs. The form of the external parts of the- repro- 

 ductive organs is remarkable; each \ -as defen -us and each oviduct 

 tuning. In the male these openings are between the 

 ninth and tenth abdominal segments, as indicated above; in th< 

 ma 1 .- ith and eighth. 



The May-fl -1 considerable- attention in popular 



writings on account of their ephemeral existence in the adult state. 



All : .'1 of the insects that li\< day. K< 



in these accounts to members of this family; and although the popu- 



illacious, il 1 e foundation in fact. Strictly speak- 



the May-fli ; some species appear twice 



annually, "iice in the spring, and again in the- autumn ; but as a rule 



one. two, or even tlr uired for the development of a 



