76 THE EEPOET OF THE ENTOMOLOGICAL SOCIETY. ^o. 36 



ADAPTATIONS IN THE STPtUCTURE OF INSECTS. 

 By Rev. Thomas W. Fyles, D.C.L. 



On a certain occasion last summer, a friend of mine was standing on a bridge, 

 which spanned a shallow creek that had a muddy bottom. His attention was taken 

 by the proceedings of a large dragon-fly that was hovering close to the surface of 

 the sluggish stream, at the shallowest part of it. The insect repeatedly thrust its 

 abdomen down through the water, and into the mud. My friend could see the slight 

 disturbance in the mud as the point of the insect's abdomen entered it and was 

 again withdrawn. The fly was depositing its eggs. Here then was revealed one 

 reason why the dragon-fly has so lengthy a tail. 



It is interesting to see one of the "Demoiselles" — Agriontdae — alight on a 

 floating leaf of a Pond Lily, and bend its long abdomen round the edge of the leaf to 

 affix its eggs on the under side — the side in contact with the water. 



The perfect fitness of every part of an insect for the functions it has to serve 

 will always be admired by the inquiring and thoughtful observer. 



In our early lessons in Entomology certain facts were impressed upon our 

 mind, viz. — that an insect is a creature that is cut into or notched ; that the notches 

 mark out the head, the thorax, and the abdomen; that the insect passes through 

 four stages of existenc'e — the Egg, the Larval, the Pupal and the Imago stages. 



In this short article I purpose to offer a few desultory remarks on the several 

 features of the insect form, and on the several stages of insect life — endeavouring 

 to show the. admirable fitness of the insect to meet, at all times, the exigencies and 

 requirements of its existence. 



The Head. In the head of an insect the striking and important features are 

 the eyes, the mouth organs, and the antennge. 



In the larger dragon-flies (Fig. 12), such as those in the genera .^shna and 

 Anax — insects of extremely rapid flight — the eyes occupy the main portion of the 

 head space. The huge compound eyes of Anax Junius are contiguous; yet they 

 allow room for three ocelli. Nothing seems to escape the glance of these splendid 

 insects ; and in the bright sunshine, when they are most active, the ease with which 

 they evade the sweep of the net of the entomologist, though it may be provoking to 

 the sportsman, must nevertheless awaken his admiration. 



FIG. 12. Dragon Fly. FiG. 13. Damsel Fly. 



In the Agrionidoe or Damsel-flies (Fig. 13),— insects of less rapid flight— 

 which can take a more leisurely view of things — the head, as Wood remarks,* 



* " Insects at Home," page 275. 



