520 Illustrations in British Zoology : — 



A remark may be here ventured on the sexual differences in 

 the more common species of dragon fly in the imago state. In 

 Kirhy and Spence^ vol. iii. p. 300., it is remarked, on the autho- 

 rity of Reaumur : — "In the Neuroptera, the female Libellii- 

 lidae are sometimes sensibly smaller, and never larger, than 

 their males." This may be true; but the remarkable abdominal 

 difference in the sexes ought not to escape observation, the 

 figure of this part in the male being long and slender, as in 

 Jig. 98. a ; and in the female shorter, broader, and more gross, 

 bearing much resemblance to the figure of the abdomen in the 

 pupa (marked h). It may, besides, be asked (for I find it not 

 stated), what time is occupied by the dragon fly, in passing 

 through the larva and pupa states into the imago ? As the 

 Libellulse are deemed highly developed insects, is it irra- 

 tional to suppose they may occupy almost as long a time in 

 the larva and pupa states as ikfelolontha vulgaris and Cos- 

 sus ligniperda are stated to do ? 



Samouelle's remarks [Compendium, p. 65,) on the dragon 

 fly family are so pertinent, succinct, and yet explicit, that I 

 must quote them also. The dragon flies " are remarkable 

 for a long slender body, and wings standing out at right 

 angles. The larvae have six feet, and move with great ac- 

 tivity in the water : . . . they are the crocodiles of aquatic 

 insects. The larvae and pupae are not very different; the 

 latter [be) have the rudiments of wings. In a fine day 

 in June, a person standing by a pond may observe them ap- 

 proach the bank, for tne purpose of changing their element. 

 Having crawled up a uiade of grass or bit of dry wood 

 [usually the withered stems and leaves* of last year's herbage], 

 the skin of the pupa grows parched, r.nd splits at the upper 

 part of the thorax ( c ). The insect issues forth gradually, 

 throws off' its slough, in a few minutes expands its wings, 

 flutters, and then fli'^s off. The sexual parts in the male are 

 placed under the thorax ; in the female, at the extremity of 

 the body. The tail of the male is furnished with a hooked 

 forceps." 



Art. VI. Illustrations in British Zoology. By George John- 

 ston, M.D., Fellow of the Royal College of Surgeons of Edin- 

 burgh. 



5. PrANI^ZA FUSCA^TA. ( 7?^. 99.) 

 CI. Crustacea, Ord. Heterobranchia, Fatn. lonellidae, Gen. Praniza. 

 This genus was proposed by Dr. Leach, a naturalist of 

 extraordinary zeal and acquirements, for a remarkable crus- 



