APPENDIX TO VOL. I. 219 



more, in all 15 flies, all females. Dr. Osborne had also 

 9 cocoons produced from presumably fertilised eggs 

 which yielded 5 living and 3 dead ? flies, only one 

 larva having perished. 



If these observations are normal they show "first, 

 there is a smaller number of flies excluded alive from 

 the cocoons ; thus, in the 282, 270, and 32 respectively, 

 came out 1 in 2, 1 in 27, and 1 in 8, while in the case 

 of the 9 cocoons from fertilised eggs, more than half 

 excluded flies, and in all but one of the remainder the 

 insects had reached the imago state ; secondly, there 

 is progressive infertility, flies from fresh larvae lay eggs 

 abundantly, their descendents much more sparingly, 

 and in the third generation hardly any eggs were pro- 

 duced ; thirdly, we see a striking increase in the pro- 

 portion of males in the second generation" (Osborne, 

 B. M. M., xxi, p. 129). No doubt a certain allowance 

 must be made for the artificial conditions under which 

 the larvae were reared, but generally Dr. Osborne's 

 observations lend support to the views I ventured to 

 enunciate in the first volume (p. 29), viz., that the 

 parthenogenetic progeny have not the same vitality as 

 those which owe their origin to sexual generation. 



DOLERUS. 



At p. 162, add- 



1ft. DOLERUS PRATORUM. 



Tenthredo pratorum, Fall., Acta, 1808, 64, 27. 



Tenthredo (Dolerus) equiseti, King., Berl. Mag., viii, 298, 225; 



Htg., Blattw., 233, 9. 



Dolerus pratorum, Thorns., Hym. Sc., i, 281, 5 ; Andre, Species, 



i, 268, Cat. 33*, 7; 

 Brischke, Beob. ii 

 Blattw. u. Holz. (2), 

 43, 5 ; Cam., E. M. M., 

 xx, 265. 



Black; segments 2 6 of abdomen, femora and tibiae, red. Eyes 

 oblong, inner orbits margined; third joint of antennae longer than 

 fourth ; tegulse black, fuscous or white ; labrum white. 



Length 4 4^ lines. 



