332 INSECTS AT HOME. 



there was no trace of either egg or larva of the latter. On the 

 23rd, six days from the date of oviposition, the Chrysis larva 

 had eaten all the store, and was full-fed. I obtained evidence, 

 by finding the exuviae, of its having cast its skin three times, 

 whilst under observation ; and from the analogy of Chrysis 

 bidentata, I believe it had done so four times altogether. The 

 stored larvoe had all been eaten, their heads alone remaining, 

 just as when eaten by the wasp grub. The larva then spun a 

 cocoon, which I know to be typical of C. ignlta. This was the 

 only occasion on which I had a feeding larva of G. ignlta, and 

 the rapidity with which it fed up astonished me. None of my 

 G. neglecta or bidentata fed up so rapidly ; but the warm 

 sunny wall on which 0. parietwin had built lier nest may partly 

 account for this, my larvae of the other two species having been 

 kept comparatively cool. 



' Chrysis hidentata, when about to deposit her eggs, search-es 

 for a full-grown larva of Odynerus sjpinijpes at, or immedi- 

 ately after, the period of spinning. 0. spinipes, on tlie com- 

 23letion of her burrow, fills up the mouth with clay long before 

 the most accessible cells can contain full-grown larvce ; but it 

 happens that, in a large proportion of cases (about half), the 

 wasp meets with some accident, and her burrow remains un- 

 completed, the cell last constructed being thus only protected 

 b}'" the wall of clay that was to serve as a party wall between 

 it and the succeeding one, had the wasp lived to complete her 

 work. Such slightly protected cells are those chosen by 

 C. bidentata for her oviposition. I once found satisfactory 

 evidence of C. bidentata having bxuTowed through half an 

 inch of the clay stopping placed by the wasp over one of these 

 cells. The parasite was in the burrow, covered with the dust 

 brought down into it by her excavation to form an entrance — 

 u passage too small for the wasp to enter, but just large 

 enough for herself ; and in the cell thus reached by her were to 

 be seen her eggs, freshly deposited. On another occasion, a 

 G. bidentata alighted on a spot I was examining, and where I 

 had partially exposed some cocoons of 0. spinipes : she com- 

 menced to carefully investigate them with her antennae, and 

 now and then to scratch away some eartli partly covering 

 them ; she did not, however, deposit any egg, possibly becausf 

 the inmates of the cocoons were not in proper condition. 



