350 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



A number of inferences might be drawn from the geological his- 

 tory of the insects as we now know it, only a few of which have been 

 indicated above. Certainly there is one justifiable conclusion, namely, 

 that our existing insect fauna is but a small fragment of the total 

 insect aggregation that has occupied the earth during the past 250 

 million years. Understanding of insect evolution depends to a large 

 extent on a knowledge of the extinct insect population. The investi- 

 gation of the fossil record has only begun, and progress is slow, but 

 the significance of the record increases with each discovery. 



REFERENCES 



1. SCUDDEB, S. H. 



1886. Systematic review of our present knowledge of fossil insects. 

 U. S. Geol. Surv. Bull. 31, pp. 1-128. 



2. Handlibsch, A. 



1906-8. Die fossilen Insekten und die Phylogenie der rezenten Foramen. 

 Leipzig. 



3. 



1937. Nene Untersuchungen iiber die fossilen Insekten. Ann. Naturhist. 

 Mus. Wien, Teil 1, vol. 1, No. 48, pp. 1-140. 



4. Lemche, H. 



1950. The origin of winged insects. Vidensk. Medd. Dansk Naturh. 

 Foren., vol. 104, pp. 127-168. 



5. 



1942. Tlie wings of cockroaches and the pliylogeny of insects. Vidensk. 



Medd. Dansk. Naturh. Foren., vol. 106, pp. 288-318. 



6. Carpenter, F. M. 



1948. The supposed nymphs of the Palaeodictyoptera. Psyche, vol. 55, 

 pp. 41-50. 



7. Mabttnov, A. B. 



1923. The interpretation of the wing venation and tracheation of the 



Odonata and Agnatha. (In Russian.) Rev. Russe Ent., vol. 

 18, pp. 145-174. English translation in Psyche, vol. 37, pp. 245- 

 280, 1930. 



8. 



1925. tJber zwei Grundtypen der Fliigel bei den Insekten und ihre Evolu- 

 tion. Zeitschr. Morph. Okol. Tiere, vol. 4, No. 3, pp. 465-501. 



9. Crampton, G. C. 



1924. The phylogeny and classification of insects. Pomona Journ. Ent. 



Zool., vol. 16, pp. 3.3-47. 



10. Forbes, W. T. M. 



1943. The origin of wings and venational types in insects. Amer. Midi. 



Nat., vol. 29, pp. 381-405. 



11. Laurentiaux, D. 



1951. Le probleme des blattes pal^ozoiques a I'ovipositeur externa. 

 Ann. Pal6ontol., vol. 37, pp. 187-195. 



12. Andee, K. 



1942. Die Insektenfauna des Baltischen Bemsteins nebst damit 

 verkniipft zoogeographischen Problemen. Kung. Fysiograf, 

 Sallsk. Handl., n. f., vol. 53, pp. 1-82. 



