308 The Life History of '' Wireivorms" 



Ovum. 



Generally broadly ovoid but varies considerably in both shape and 

 size. Average dimensions of ten o\'a -54 mm. x -43 mm. and therefore 

 slightly smaller than those of A. obscurus. One ovum found was almost 

 bean-shaped and measured -475 x -43 mm. In this species also the shell 

 is transparent and almost smooth, the whole appearing to be milky 

 white from the colour of the contained yolk and embryo. 



First Larval Instar. 



In general appearance the larva is extremely like A. obscurus at the 

 same age. The average length during the first day after hatching is just 

 under 2 mm. (1-9), ranging from 1-25 to 2-25 mm. in a dozen specimens; 

 the breadth across the prothorax about -25 mm. The ventral surface is 

 flat, the dorsal arched, but less so than in older larvae. Colour milky 

 white. It is difficult to see any material difference in the sculpture of 

 the dorsal surface in preserved specimens, but in life the young sputator 

 is a trifle more rugose and punctulate. 



The head is about equally long and broad, measuring the length 

 from the base of the mandibles to the occiput and the breadth across 

 the broadest part, a little anterior to the middle. It is longer than either 

 the nieso- or meta-thorax. As in A. obscurus, the mandibles (Text-fig. 1 a) 

 are brown at the apex and broader in proportion to their length in the 

 first than in the final instar. The nasale or clypeal process is represented 

 by an entire rounded projection above the mouth. Beneath this, traces 

 of the sub-nasal process are visible, usually as a minute notched process 

 at the base of the nasale, with one or two smaller rounded thickenings 

 of the chitin beyond the lateral margins of the nasale. In the antenna, 

 the third or supplementary segment is longer than the conical ventral 

 process at the apex of the second segment, but much less so than in 

 mature larvae. At this stage, it is also longer in proportion to the whole 

 antenna than in older larvae. 



Of the setae with which the tergites are furnished, the posterior row 

 is, as usual, longer than the anterior, but they are not so long as the 

 segments to which they belong. Those of the two rows on the prothorax, 

 anterior and posterior, are of about equal length. The setae of the head 

 and also those surrounding the cauda are shorter than these. Subsequent 

 measurements of the setae of A. obscurus at the same stage show that 

 the relative proportions previously given (Pt. II, p. 195) must be 

 amended, those on the abdominal segments being the longest, while 



