506 
Max Morse 
Comparisons. 
We sliall now attempt to bring the present account into line 
witli that of other workers on tbe Orthoptera. It will not be necessary 
to review extensively tbe literature on tbe spermatogenesis of tliis 
group, for tliis has been done recently quite exbaustively by Davis 
(’08), Robertson (’08) and Jordan (’08) wbile Wilson (’09) bas 
summarized tbe knowledge of tbe idiocbromosomes in all groups 
wbere such bodies bave been found. The reader may refer to tbese 
papers for bibliograpbies. 
a) Tbe spennatogonial and oögonial chromosomes. Wbile the 
spermatogonial nurnber of chromosomes bas been ascertained by 
several workers for different species, the somatic nurnber bas been 
determined for both sexes of tbe same species only in the following 
Orthoptera ; 
cf $ 
Blatta germanica Blattidse 23 24 Wassilieff (’07). 
Aplopus mayeri Pbasmidie 35 36 Jordan (’08). 
Anisolabis maritima Forficulidte 24 24 Randolph (’08). 
Hippiscm tnberculatus Acrididm 23 24 Davis (’08). 
In all bat one case, the idiochromosomes are unpaired or odd cbro- 
mosomes, tbe exception being tbe earwig, wbere an even nurnber of 
chromosomes occurs in the spermatogonia (Randolph ’08, for Aniso- 
labis maritima and Zweiger ’06, for Forficula auricularia) , wbile 
in one case, at least (Randolph ’08), tbe oögonial nurnber is tbe 
same as tbe spermatogonial. 
Moore and Robinson (’04) state that "the nurnber of ckromo- 
somes in tbe premaiotic division in P. americana is thirty-two, but 
at tbis stage 1 ) thirty-three chromatic bodies may be counted witbin 
tbe nuclear membrane.” Farmer and Moore (’04) find that tbe nurnber 
"appears generally to be tkirty-two; many figures bave been en- 
countered in whick tbe nurnber appears more or less than tbis by 
one, two or even more.” The present writer does not find a varying 
nurnber of chromosomes in bis material, except when tbe cells have 
been disarranged by the knife, in wbich case, tbe nurnber of ckro- 
mosomes may be less than tkirty three, but never greater. Tbe 
*) Spermatogonial. 
