the Growth and Habits of Carausius morosus. 349 



my shortest black measured 69 mm., and the two other 

 blacks measured 74 and 78 mm. respectively (the average of 

 34 specimens from one parent being 80*1 mm.). I did not 

 get the gradations in colour up to dark brown or black 

 which Schleip shows on his coloured plate — in fact, between 

 the dark brown (almost black) and the darkest fawn there 

 was a big gap. 



Incubation-box. 

 The eggs for incubation were placed in small glass- 

 capped circular card-board boxes, with a thin layer of sand 

 on the bottom. The sides were perforated by means of 

 pins, and the boxes numbered on the inside {not on the 

 lids). These boxes were placed in rows in a shallow wooden 

 box (an old chocolate manufacturer's packing-box), the 

 necessary moisture being provided by wet folds of clean 

 blotting-paper well soaked afresh daily. The wooden box 

 being badly made with an ill-fitting lid allowed amply for 

 the circulation of the air. 



Incubation. 



In the incubation-boxes the incubation varies from 

 137 days to 297 days, thus covering an extreme range of 

 160 days. Those nymphs which hatched out up to 254 

 days' incubation were healthy and apparently in normal 

 condition, but one which hatched out at the end of 297 

 days was very feeble, drank sparingly, and, although it 

 was ready for a drink every one of the 6 days it lived, its 

 abdomen remained contracted laterally and it did not eat 

 at all, while usually about 50% have commenced eating 

 on the third day after hatching out. 



The accompanying table shows that more than 50% of 



Table I. — No. of Days of Incubation. 



