68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



forms is, therefore, as Willem contends, a specialized condition ; it 

 results in the formation of a gonad resembling a single testicular or 

 ovarial tube of Thysanura and Pterygota, but which cannot be a mor- 

 phological counterpart of the latter, since the tubes of a compound 

 gonad are developed as lateral outgrowths of the primitive sac. 



The development of the eggs in the ovary of Podura is described 

 by De Winter (1913), who shows that the oocytes are proliferated in 

 rows extending peripherally from the germarium, and that they be- 

 come enmeshed in a reticulum of cells that grow inward from the 

 outer epithelium of the ovary. The distal oocytes, by reason of their 

 closer contact with the blood, are the better nourished and develop 

 into the functional ova, while the more central cells become degen- 

 erate, and some of them in contact with the outer cells are absorbed 

 by the latter. The general structure of the ovary of Podura, with 

 the peripheral development of the ova, and the close resemblance to 

 the ovary of Lithobius, De Winter contends, shows that the poduran 

 ovary is not derived by condensation or reduction from the com- 

 pound type of insect gonad, but is a gonad of generalized structure, 

 and represents the most primitive type of ovary found among the 

 insects. 



No verified observations have yet been made on the exact manner 

 of insemination of the female by the male in Collembola. The curious 

 mating habits of the Sminthuridae, however, have long been known 

 and have recently been described in detail by Falkenhan ( 1932) and by 

 Strebel (1932). The male approaches a female and with his antennae 

 grasps the antennae of the female, the male antennae being specially 

 adapted for clasping by a modification of the second and third seg- 

 ments. The male is then lifted by the female, who carries him around 

 suspended before or above her body while she goes about the affairs of 

 her ordinary life. The male remains inactive with his legs folded 

 against the body, and is thus transported by the female for a time vary- 

 ing from a few hours to as long as a day and a half, but with intermis- 

 sions the carrying of the male may be continued for four or five days. 

 Only one writer, Lie-Pettersen ( 1899) , claims to have observed the act 

 of insemination ; according to his account a male while suspended by 

 the female was seen to emit a drop of spermatic fluid, which fell on the 

 wall of the glass tube containing the insects, whereupon the male 

 released himself, with his fore legs smeared the drop on his mouth 

 parts, and then inserted the latter into the genital opening of the 

 female. Neither Falkenhan nor Strebel, after prolonged observation, 

 saw any act on the part of the mated sminthurids such as that de- 

 scribed 1)y Lie-Pettersen. Falkenhan postulates, however, that insemi- 



