OF CERTAIN CHALCIDID^E AND ICHNEUMONIDjE. 93 



of the Mole Cricket* ; although the precise structure and mode of termination of the 

 trachea? now described appear to have been unknown to him. Further, they may assist 

 to explain the mode of coloration of the tracheae in the experiments of MM. Alessandrini 

 and Bassif, and M. BlanchardJ, and also in others, yet unpublished, by myself, made 

 on the larvae of Clissocampa Neustria, in July 1837. 



EXPLANATION OF THE PLATE. 

 Tab. IX. 



Fig. 1. Ichneumon Atropos, imago state. 



Fig. 2. a, b, c, d, larvae of Ichneumon in various stages of growth. 



Fig. 3. Full-grown larva (a) between the adipose tissue (b) and stomach (c) of a pupa of Sphinx ligustri. 

 (d) brain ; (c) muscles of the thorax ; (f) heart ; (g) testes. 



Fig. 4. Perfect Ichneumon escaping through the back of a destroyed pupa. 



Fig. 5. Upper and under surface of the head of the larva, (a) antenna; (b) face or clypeus ; (c) labrum ; 

 (d) mandible; (e) maxilla; (/) labium. 



Fig. 6. Magnified view of antenna of larva of Ichneumon. 



Fig. 7- Antenna of larva of Monodontomerus. 



Fig. 8. Alimentary canal, &c. of larva Ichneumon, (a) antenna; (b) brain; (c) optic nerves; (d) salivary 

 glands ; (e) oesophagus ; (/) stomach ; {g) intestine ; (h } i) colon and rectum ; (k) Malpighian 

 organs. 



Fig. 9. Nervous system of the larva. 



Fig. 10. The imago Ichneumon dissected ; letters as before. 



Fig. 11. Alimentary canal and appendages of Microgaster. 



Fig. 12. Tissues of the alimentary canal in the larva Ichneumon, (a) muscular layer or tissue; (6) glan- 

 dular; (c) mucous. 



Fig. 13. Respiratory system in the abdomen of perfect Ichneumon. 



* Phil. Trans. 1826, p. 235. 



t Gazette Medicale de Milan, t. vi. and Annales des Sciences Nat. 3 me Serie, torn. xv. J hoc. cit. torn. xv. 



VOL. XXI. 



