312 



I find from an examination of a large series of specimens of lineata 

 that the armature particularly of the lateral protuberances is subject 

 to some variation, and have shown in the accompanying diagram (Fig. 

 47) the maximum armature; but the chief characters distinguishing the 

 larvae, namely, the stigmata and particularly the armature of seg- 

 ments 9, 10 and 11, are constant in lineata at least, and also in the few 

 larvae of hovis which I have had opportunity of examining. 



DESCRIPTIVE DETAILS. 



The egg. — The egg, including the pedicel or clasping base, is 1 mm. 

 long and 0.02 mm. wide at the greatest diameter. In color it is dull 



yellowish white, and the surface is 

 smooth and shining. As may be seen 

 by the illustrations (Fig. 44 a, d), the 

 egg consists of two distinct parts, viz, 

 the egg proper and the clasping base 

 which firmly secures it to the hair and 

 connects with the egg proper by a thin 

 but rather wide pedicel. This base is 

 made up of two lips or valves, which 

 close over the hair and thus give a 

 ver}' secure attachment. The egg is 



K I 



narrow, ovoid, broadest at its middle 



Fig. 47. — Hypoderma lineata— diagram of 

 maximum armature (original). 



and larger at the base than at the tip, 

 whicli is more or less abruptly and ob- 

 liquely truncate. (Fig. 44.) 



The LARVA: First stage. — This stage 

 (Fig. 44 p), when ready to leave the 

 egg^ or when first hatched, is 0.08 mm. long by 0.02 mm. in width, 

 tapering above. Within the egg it just fills the cavity, and may be 

 seen through the shell and quite readily removed. It is dull white in 

 color, with the surface from the second to the twelfth joints distinctly 

 and densely spinous. The armed area occupies the entire surface of 

 these joints, except a narrow lateral free space. The arrangement of 

 the spines on these joints, except the last, is uniform, with perhaps a 

 slight increase in the size of the spines from the second to the eleventh 

 joint. The armature of these joints and of tlie anterior half of the 

 twelfth consists of a rather prominent and posteriorly directed row on 

 the anterior margin of ea<;h joint, followed by numerous smaller prickles 

 which decrease in size and abundance towards the posterior margin of 

 the joint. The posterior half of the terminal joint is armed with very 

 much larger and slightly curved prickles or spines, wliich point poste- 

 riorly on one side and anteriorly on the other. (See Fig. 44 //.) The anal 

 spiracles are represented by dark circular spots, and terminate in two 

 prominent spines. The anterior spiracles appear as two minute eleva- 

 tions, and the mouth-parts consist of two dark-brown crescent- shaped 



