THE NOCTUINA. 1 27 



generally of moderate size ; the hind wings are usually much 

 folded under the fore wings, and the inner margins of the latter 

 in repose frequently overlap. The caterpillar generally has 

 sixteen legs, and, consequently, few loop when walking. Their 

 chrysalis is usually found underground. The moths of the 

 QuadrijidcB have generally broad wings, which sometimes are 

 of very large size ; the hind wings are but little folded, and the 

 inner margins of the fore wings rarely overlap in repose. The 

 caterpillars rarely have sixteen legs, and more frequently are 

 noticed with fourteen or twelve, and many of them loop more 

 or less when they walk. The chrysalis is rarely found under- 

 ground. 



There are some Noctuina which particularly put one in mind of 

 the Bonibycina, and they are the Acronycta and the allied genera 

 (forming the Bombycoidd). A greyish-black caterpillar, with a 

 broad yellow line down the back, having a large black hump on 

 the fifth segment of its body, and a short black one on the twelfth, 

 is very common during the autumn upon the elms, limes, and 

 upon most fruit trees. When it has reached its full growth the 

 insect descends from the branches and hides itself, either in the 

 cracks in the bark of the trunk or in holes at the foot of the 

 tree, where there is safe shelter, and then spins a light cocoon, 

 and undergoes its metamorphosis. The chrysalis remains in its 

 quiet condition until the month of June in the next year, when 

 the metamorphosis into the moth takes place. The moth may 

 be seen during the day-time upon trunks of trees, or upon 

 ^walls, and may be recognised by a curious mark on the wing, 

 which resembles a Greek letter. Hence the moth is called 

 Acronycta psi. In England it is called the Common Dagger. 

 Now, Acronycta tridcns has a caterpillar which is orange red 

 in colour, and which has a small black hump on the fifth, and 

 a whitish black-crowned hump on the twelfth segment. This 

 caterpillar differs, therefore, in its colour and humps from the 

 common dagger caterpillar. But the moths of the two species 

 resemble each other perfectly. The question arises at once in 

 the mind, is this diversity of colouring and humping of veiy 

 great importance, and of any specific value .'' It has been noticed 

 in former pages that the caterpillars of succeeding broods of the 



