440 NATURAL HISTORY OF ARTHROPODS. 



nearly black spots so extended as to cover a large part of the wings. The hind 

 wings are pale grayish. The females deposit thirty or more eggs on the kernels 

 of wheat or other grain ; and, as soon as these hatch, the young caterpillars eat into 

 the grain, feeding on its substance, till they are mature, if it contains a suflBcient 

 quantity of food, otherwise they leave, and attack another which they attach to the 

 first by their silken threads. At maturity they leave the grain, and spin a cocoon in 

 some secure place where they pass the winter, changing to pup£e in the spring ; and 

 after a few weeks the moths emerge. 



The cabbage Plutella {Plutella xylostelld) expands about three-fourths of an inch, 

 and has ashy-gray fore-wings, with an irregular whitish stripe along the hinder margin, 

 and a similar one along the top of the thorax. The caterpillars are of a grayish color, 

 with pale yellowish heads. When mature, they spm a loose, gauzy cocoon on the 

 surface of a leaf, within which the pupa is readily seen. There are two or more broods 

 in a year, according to the length of the season. This species has become established 

 in all parts of the world, and is often so abundant on the outer leaves of cabbages and 

 other cruciferous plants as to cause a great amount of damage. 



The species of Lithocolletis are all minute, but most beautifully colored. The 

 larvae are all leaf-miners, and each species usually confines its depredations to a single 

 species of plant. The moths fly rather sluggishly, and sometimes appear in large 

 numbers. The only other form which we can mention is called the Angoumois 

 grain-moth {Sitotroga cerealella) ; it apjjears to be a native of Europe, and has been 

 known in this country for nearly a century, proving very destructive to wheat, 

 barley, oats, and corn. The moths expand a little more than half an inch, and the 

 fore wings are ochre yellow, with a few minute, black sprinkles. The hind wings are 

 gray. The females lay from sixty to ninety eggs on the young kernels in the field or 

 on the grain stored in bins. The eggs hatch in from four to seven days; and the 

 minute caterpillars eat their way into the kernel, remaining in this state during the 

 winter, in a cocoon which they spin in the grain, and within which they pass all their 

 transformations. It is stated that they may be destroyed by heating the grain to a 

 temperature of 130° F. for five hours, without injuring the vitality of the seeds. 



The family of moths known as the ToETEiciDiE is of considerable size and of wide 

 distribution, extending from the Arctic to the most southern regions. While some 

 species are found only in limited areas, others, as the codling-moth and the grape-berry 

 moth have been carried to all parts of the world, wherever their food plants are grown. 

 These insects, though small in size, are very prolific, and, unless reduced by their 

 natural enemies, would cause an amount of damage to the jDlants or fruits which they 

 attack entirely out of proportion to their diminutive size. They are generally of 

 rather modest hues, though a few are of great elegance and remarkable for their 

 beauty. They are rather crepuscular in their habits, the greater portion of them 

 flying about sunset. 



Their bodies are moderately stout, and the heads are clothed with rough scales 

 which stand erect. The ocelli are present in the majority of the species ; the palpi 

 curved up against the front, or extended forward in a line with the body, sometimes 

 twice or three times as long as the head. The antennae are simple or finely ciliated, 

 and, in a very few species, pectinated. Some species have the thorax smooth, while 

 others have a tuft of scales on the posterior portion. The abdomen is without tufts, 

 except the hairs at the end which are sometimes quite numerous, forming the so-called 

 anal tuft. The legs are of medium size and length, the middle tibiae having a pair of 



