10 



The whole time — from the appearance of the fifteenth egg to 

 the appearance of the thirty-fourth — was 208 minutes, giving 

 an average of nearly eleven minutes for each egg, including 

 interval. The whole thirty-four eggs would, therefore, 

 probably occupy a period of six hours. 



First 14 (estimated) 140 minutes. Average 10 

 E gg 15— l 9 (observed) 50 „ ,, 10 



,, 20 — 27 (observed) 88 ,, ,, 11 



,, 28 — 34 (observed) 80 ,, ,, nf 



. 358 



The insect occupied while laying its eggs the usual position 

 when at rest, with its head low and partly hidden by the 

 mesothorax. The abdomen was lifted then lowered again 

 on dropping each egg, and after a period of quiescence the 

 same movements were followed by the raising of the abdo- 

 men and the appearance of another egg. The eggs — laid in 

 an irregular heap — were perfectly spherical, white, with a 

 faint testaceous tinge and shining ; average diameter '172 

 m.m. 



EGGS AND YOUNG OF ISOTOMA PALUSTRIS. LBK. 



The first batch of eggs observed were a cluster of some 

 thirty or forty laid in an irregular heap, December 23rd, 

 1 88 1. They were globular, shining and pale testaceous 

 yellow. Three more clusters were laid on the 28th, the 

 eggs in one of which were white with only an exceedingly 

 faint yellow tinge. Amongst other clusters laid about this 

 time, one on the 6th of January, was fulvous, darker and 

 brighter in colour than any of the preceding batches, so 

 that it is evident the colour of the eggs is variable, even 

 when first laid. On the 5th of January the eggs of the first 

 batch (December 23rd) had changed in colour to purplish 

 red, and on the morning of the 10th most of the eggs had 

 hatched out. The young Isotoma is pale purplish red, bluish 

 purple on the antennae There are no markings excepting 

 the dark eye-patch, and a dark spot with fainter streak 

 leading forwards from it, on the posterior part of the head. 

 The head is large in proportion to the body, antennae short 

 and thick, with the terminal joint much larger than in the 

 adult form. The whole body is covered all over with pale 

 hairs. 



EGGS AND YOUNG OF ISOTOMA ARBOREA. L. 



The eggs of /. avbovea appear to be laid later in the season 

 than those of /. palustris. The first batch observed were laid 

 March 20th, 1882, and we had not another cluster laid until 

 March 31st. These eggs were globular, yellow, and shining 

 very much, resembling those of I. palustris. On the 9th and 



