68 CALIFORNIA STATE COMMISSION OP HORTICULTURE. 



cylindrical, and is composed of twelve rings or segments, besides the 

 head. The head is the most specialized part of the larva. It is usually 

 covered by a horny plate, often divided down the middle into two equal 

 parts. The jaws are broad and strong, serrated or toothed on the 

 edges, with the under lip or labium well developed, while the maxillaB 

 and palpi in most species are rudimentary. They differ very greatly 

 from the mature insects; in fact, it may be said that they do not 

 resemble them in any respect. In the larval form, caterpillars are 

 vegetable feeders and are very destructive; their mouth parts are 

 formed wholly for biting and chewing, while, in the perfect insect, these 

 are entirely changed, and it lives by suction. The internal organs and 

 all the external organs are changed in the process of transformation. 



The first three segments behind the head are the thoracic segments, 

 and these carry the jointed feet, which afterwards develop into the feet 

 of the mature insect. These are known as the true legs. The remaining 

 segments, usually nine in number, are known as the abdominal seg- 

 ments, and on these we find the false or prolegs, varying in number 

 from two to five pairs. These are provided with a circle of minute 

 hooks, in the place of feet, which enable the caterpillar to cling fast to 

 the plants upon which it feeds. These prolegs disappear in the mature 

 insect. Most caterpillars have sixteen legs, including the true and false 

 legs. The loopers, or measuring-worms, however, have but ten, while 

 the bag-worms have but six. 



Suborder RHOPALOCERA. (Butterflies.) 



While the moths are the most important branch of the Lepidoptera, 

 greatly exceeding in number of families and species the butterflies, and 

 are of much greater economic importance from either a beneficial or 

 an injurious standpoint, yet the former are the more widely known 

 and admired largely owing to the nocturnal habits of the greater part 

 of the moths, and also to the fact that a very large portion of them are 

 obscure in coloring, while nearly all the butterflies are attractive. 



Butterflies are separated into five families, representatives of all of 

 which are found in California. These are: 



1. Nymphalidse, the Brush-footed Butterflies. 



2. Lemoniidse, the Metal-marks. 



3. Lycrenidse, the Blues, Coppers, and Hair-streaks. 



4. Papilionidse, the Swallow-tails, etc. 



5. Hesperiidre, the Skippers. 



The family Nymphalldse is distinguished from all other butterflies by 

 the fact that in both sexes the first or prothoracic pair of legs is greatly 

 dwarfed, useless for walking and carried folded up against the breast. 

 On this account, members of this family are sometimes known as four- 



