( HKOMOSOMES IX COREID HEMIPTERA. 113 



The former type of egg develops parthenogenetically, the latter 

 only being capable of fertilization, it is supposed. In some 

 somatic tissues, such as the ovary sheath, there are more than 

 the diploid number of chromosomes, as in the bee and in Ascaris. 

 In a later brief communication, however, Doncaster ('ioa) states 

 that hi- observations on the polar mitoses may require revision 

 ami th.it the behavior of the chromosomes in Nematus ribesii is 



lithe -ult to follow that it is doubtful if a satisfactory interpret a- 

 ti"n can 1" obtained in this species. In a very recent paper, the 

 same author Ciofr) describes in detail the maturation, fertilization 

 .Hi'] i-.irly eleavagc of Neuroterus lenticularis (Cynipidae). Here 



in -ome of the results are quite novel. The mitoses of the 

 primiti\r .\ a found in young female larvae of the summer gi -in T,I- 

 t ion (oni.iin about 2o chromosomes, like those of the somatic 

 cells. In the maturation of the summer eggs apparently two 

 di\i-ion- ...cur, the female pronucleus probably containing 10 

 < In i niic.- is. The eggs are fertilized and in the cleavage spin- 

 die- about 20 chromosomes appear. The results on the matura- 

 tion ,,i tlu- spring (parthenogenetic) egg are so anomalous that it 



ms l.--t to quote from Doncaster's own summary (loc. tit., p. 

 [O2 "The maturation of the spring egg has not yet been sutli- 

 i it ntl\ -tuilied, but it appears that some eggs undergo at le.i-t 

 OIK in. it mat ion division, others probably none. In eggs in which 

 in.itnrai ion has occurred segmentation mitoses show 10 chromo- 

 BOmes; all the eggs laid by one individual female in which tlie 

 c htoiiio-oincs could be counted were of this type, and it is sii^- 



ted that the-e develop into males. In the eggs laid by other 

 1'emale-. however. 2O chromosomes appear in the segmentation 

 di\ i-ion-; in these, polar chromosomes appear to be absent, and 

 it i- prob.ible that there has been no maturation division, and that 

 the \\ould develop into females." It will be seen that no 



definite conclusions can be drawn without further confirmatory 

 observations. Schleip's ('08) observations on the polar body 

 formation in Formica sanguined were confined chiefly to the 

 part hen.. ^onetic egg. He found in the latter the haploid number 

 of chromo-omes to be about 24 in the maturation spindles and 

 female proiiiu lens. This number also appears in the first clea- 



e nmleii-. In the fertilized egg, the number of chromosomes 



