104 PROTECTION OF PLANTS — 1923-24 



slightly elevated, dark brown tubercles, trapezoidally arranged, situated 

 lateral!}^ and above the stigmata, in the centre of each segment, is a brown tu- 

 bercle; and beneath the stigmatal opening another tubercle, not so well defined. 

 Each of these wart-like bodies has a long, erect, fine, hair 3 to 4 mm. long, those 

 of the final segments are somewhat longer and coarser. The true legs concolo- 

 rous with venter, are three jointed, with tarsal claws sharp pointed and curved. 

 The prolegs yellowijsh and fleshy, each with a fringe of reddish-brown crotchets 

 pointing inward. They are situated on the third, fourth, fifth, sixth and tenth, 

 abdominal segments. The breathing spiracles are large and prominent with 

 outer edges coloured brown, placed laterally on each segment of tjie abdomen, 

 (excepting the last two) abou?t midway, with a tendency cephalad. This is 

 more pronounced in the anterior segments. The prothoracic st|igmata are 

 situated well down near the transverse posterior margin of the segment, one 

 on each side. 



The full grown female larva is readily recognized by its size. It is a thick 

 fleishy grub, clull greenish-white in color and reaches a length of 65 mm. and 

 width 17 mm. The head is light mahogany and recedes into a hood-like, pro- 

 thorax which is slightly coloured with brown; mouth parts dark; mandibles 

 large and horny. There is a group of three spines immediately in front of the 

 prothoracic spirale. In first stage larvae, howe/er there are only two in the 

 group. Thi,s characteristic is very distinctive of the cossid larvae. Both meso- 

 thorac'c and m,eta-thoTacic sections have transverse lunar-shaped markings, 

 that ot the former being more pronounced. The coloured tubercles so noticeable 

 during the first and second years are now very indistinct. The two spines situat- 

 ed just under each abdominal spiracle are arranged close together; this is pecu- 

 liar to the genus Prionoxystus. The prolegs are large and flejShy, each bearijig 

 an oval Crown of coral-red crotchets which are arranged in a circle facing inwards. 

 These crotchets are triordinal, that is, they are of three different lengths. The 

 anal s.^gment supports two fleshy processes which have a semi-circular fringe of 

 red crotchets, also triordinal. The heart flow can be very plainly sean beneath 

 the pale skin. 



The measurement of a number of head capsules suggests the likelihood 

 of five moults. 



Approximate measurements of larvae, according to sex, to indicate the development at end of 



each season. 



Male Female 



1st season grov^th from fj to 1.5 rrm. 1st season grovi^th from 5 to 20 mm. 



2nd " " " 15 to 25 nm. 2rd " " " 20 to 45 mm. 



3rd " " ' 25 to 26 irm. 3rd " " " 45 to 65 mm. 



Average Pupal Case for male — 45 mm. 



Average male Larva — 65 mm. 



Average Pupal Case for female — 25 mm. 



Average female Larva approx. — 36 mm. 



