[September 
274 Psyche 
high in Ancistrocerus as it has been reported for particular 
colonies of Polistes. 
The Sex of the Host 
As far as can be judged from our data both sexes of the 
host are attacked with equal readiness. The following is a 
summary of the cases in our list in which the sex of the 
host is known. In giving these and following figures we 
have not thought it necessary to incorporate the data so 
admirably summarized by Pierce (1909, 17-23; 1911, 487- 
489; 1918, 392-393, 396-397), and have confined ourselves 
to those in the above list. 
Males Females 
Masaridinse 8 4 
Montezumia 
Males 
0 
Females 
5 
Zethinse 
1 
4 
Polybiinse 
4 
15 
Eumenes 
7 
8 
Ropalidia 
1 
1 
Odynerus s.l. 
50 
49 
Polistes 
13 
56 
Monobia 
3 
1 
Vespa 
2 
6 
Where, as in Polistes and the Polybiinse, decidedly more 
female than male hosts are known, this must undoubtedly 
be attributed to the fact that females of these groups are 
much more commonly collected. 
Position of the Parasite in the Host 
As would be expected, the parasites extrude in about 
equal numbers on the two sides of the host. A summary of 
the cases in our list for which the side is recorded gives 
132 on the right and 141 on the left. 
A very strong preference is shown for a dorsal position. 
In our list only ten cases of extrusion between the sternites 
appear. One of these occurs in Vespa and was recorded by 
du Buysson. Of the nine cases which we have observed, 
seven occur in Polistes and two in Pachodynerus. In each 
of these nine cases the unusual, ventral position is obviously 
due to crowding, for in four cases the parasite appearing 
ventrally is one of three in the same host; in two cases one 
of four ; in one case one of five ; and in one case, where two 
