.S94- 
317 
[Packard. 
judging from niy figure of wluit are apparently two diverticula of 
the jjosterior third of the digestive tract iu the hxrva when ready 
to hatch (Fig. 1, ur.t.). Mr. Burgess in liis notes states that he^ 
made 'out spiracles "on every segment but the first three," but 
the one on the last segment vvas marked doubtful, and I have 
erased it from his drawing, as no insect larvae are known to have 
a pair of spiracles on the last segment. 
The egg-shell burster. — This is an interesting example of the 
development of a temporary larval structure, and so far as known 
is a solitary instance of such a structure in insects. The 
only other cases known to me among the Arthropoda are the egg- 
FiG. 3. Details of larva of FaUx, cauls ; A, t6, egg-breaker ; Ibr, labrinn ; 
m.c, maxilla; mxJ , labiiun; md, right and left mandibles; ant, aiiteiuui; B, 
5-8 segments behind the head showing the ganglia; C, end of the body, 
sp, last pair of spiracles, with the caudal stylets. — Burgess del. 
shell burster or boring apparatus on the embryonal cuticle over 
tlie head of the diplopod myriopod, Strongiflosoma gueri7iu, and 
on the third pair of mouth-parts of Geophilus, figured and 
