ANATOMY AND PHYSIOLOGY 71 
described by Cheshire, is rather complex. Briefly, the sheath 
serves to open a wound and to guide the 
darts; these strike in alternately, inter- p 
rupted at intervals by the deeper plung- 
ine of the sheath (Fig. 81, A). The 
poison of the honey bee is secreted by 
two glands, one acid and the other alka- 
line? ‘Ihe former (Fig. 82) consists of 
a glandular region which secretes formic 
acid, Of ‘a reservoir, and a duct that 
empties its contents into the channel of 
the sheath. The alkaline gland also 
opens into the reservoir. It is said that 
both fluids are necessary for a deadly 
effect; and that in insects which simplv Extremity of abdomen 
- oie ny OTL oe ne a of a male beetle, Hy- 
paralyze thei prey, as the solitary WASPS,  gesshitue ventral aeneee 
the alkaline glands are functionless. g, genitalia; p, penis; 
Br ee ae oo eee 
vi, wv, pairs of valves 
Male Genitalia——The penis may be  ercosine the penis; 601 
hollow or else solid, and in the latter case — sterna of abdominal seg- 
the contents of the ejaculatory duct are ey a re 
spread upon its surface. Morphologically, the male gona- 
Pew ot pophyses correspond to those of the 
female. The penis (Fig. 83) rep- 
resents the two inner valves of the 
ovipositor and is frequently enclosed 
by one or two pairs of valves. In 
phemerida the two inner valves 
are partly or entirely separate from 
each other, forming two intromit- 
tent Organs (ios $4)).. 
In male Odonata, the ejaculatory 
duct opens on the ninth abdominal 
Extremity of abdomen of a segment, but the copulatory organ 1s 
male May fly, Hexagenia varia- a apse ‘> : en 
Bit meer eaepeees 2.6. ¢- placed on the tinder side or thersec- 
cerci; cl, cl, claspers; 4, 4, in- ond segment, to which the spermato- 
tromittent organs. 2 y 
zoa are transferred by the bending 
of the abdomen. At copulation, the abdominal claspers of the 
