106 
Psyche 
[December 
a specialization, possibly accompanying a partial or total 
shift in glandular function from a defensive organ to a 
poison gland. Since, in all the aquatic bugs studied, the 
orifice is always near the base of the beak, bordering on 
the maxillary plate (Benwitz, 1956), any change to this 
location from that seen in Gelastocoris would have to have 
occurred just before the primitive line diverged into sep- 
arate aquatic families. Against this theory, however, is 
Macgill’s observation that the opening of the glands in 
the gymnocerate Dysdercus are at the base of the labium. 
This suggests that this location of the orifice is the primi- 
tive condition, and was found in the Proto-Heteroptera 
(to use the term of China, 1955) before the Gymnocerata 
and Cryptocerata diverged. If this theory is correct, the 
more posterior position of the orifice in Gelastocoris is a 
secondary acquisition. Why such a shift should take place 
is not clear, however, since the gelastocorids are predators, 
like their aquatic relatives, and orifices associated with 
the labium, which could allow the glands to serve as poison 
glands, would be advantageous to them. Although the sec- 
ond of these theories appears at this time to be the more 
commendable, more information on the presence or ab- 
sence of cephalic glands in other Heteroptera, and on the 
location of their orifices, is needed to shed further light on 
this problem. 
Literature Cited 
Banks, C. J. 
1939. Cephalic glands in the Corixidae. Proc. R. Ent. Soc. Lond. 
(Ser. A), 14:83-85. 
Becker, E. 
1929. Zum Bail des Kopfes der Rhynchoten. I Teil. Bail des Kopfes 
von Naucoris cimicoides L. Rev. Zool. Russe, 9:1-53 (in Russian) 
and 54-96 (in German). 
Benwitz, G. 
1956. Der Kopf von Corixa punctata 111. ( geoffroyi Leach ) (Hemip- 
tera-Heteroptera). Zool. Jahrb. (Abt. Anat.), 75:311-378. 
Bordas, M. L. 
1905 a. Sur les glandes salivaire cephaliques et metathoracique des 
quelques Hemipteres. C. R. Acad. Sci. Paris, 140:595-597. 
1905 b. Les glandes salivaires des Nepidae ( Nepa cinerea L.). Anat. 
Anz., 26:401-406. 
