INSTRUCTIONS FOR COLLECTING INSECTS. 185 



The glass merely stands on the rim of the box, and should not be 

 perfectly air tight; and the vivarium should be exposed to the change 

 of temperature between night and day, so that the included atmo- 

 sphere, by its expansions and contractions, may be also renewed from 

 the external air. It should never, however, be exposed to the direct 

 rays of the sun, but always kept in the shade. 



To those who may regard this apparatus too expensive, another 

 form is recommended, but it is neither as convenient nor successful, 

 except in the case of leaf miners and micro-lepidoptera. The top of 

 a glass jar, at least five or six inches in diameter, is ground down on 

 a piece of sheet lead with emery and water, so as to be perfectly level, 

 and to receive accurately a piece of plate glass as a covering, in order 

 to prevent the escape of moisture. The bottom of this is covered with 

 moistened sand, a little loam, and the surface with moss. Into this 

 the food, plant, and caterpillar may be introduced, with the expecta- 

 tion that the insect will do very well. It is, however^ apt to become 

 foul from the accumulated "frass," and is inconvenient to clean. 



In order to rear leaf-mining larvae that never leave the leaf in 

 which they are found, or at least not until about to transform, a com- 

 mon large drinking glass, the top of which has been ground level 

 and covered with a piece of plate glass, answers a very good purpose. 

 The bottom should be covered with ichite sand, moistened, but no 

 water should be permitted to rest on the surface. It is not necessary, 

 of course, to place in this apparatus anything more than the leaf, 

 with a portion of its stem containing the leaf miner. The collector 

 should provide himself with a tin canister in which to carry the leaves 

 containing leaf miners during his entomological excursions. 



A still cheaper and very effectual breeding cage consists of a frame 

 of any convenient size, say twelve inches square, covered with bob- 

 binet, and with a door in front. The bottom must be of wood, and 

 the plant may be kept fresh for several days by inserting it in a vial 

 half filled with water. 



We have now to touch on what devolves upon the observer, in 

 making use of these contrivances, to enable him to record the habits 

 of larvae, and to make good and useful descriptions. In the history 

 of the life of any being one of the most valuable traits of the observer 

 is truthfulness, not that we mean to say any one would wilfully mis- 

 represent what he sees, but that he should be truthful in recording 

 what he sees and knows to be facts, not what he may imagine or con- 

 jecture; and however strange it may appear to those not familiar with 

 these studies, the temptation or inducement to depart from what is 

 evidently so proper is often strong and of frequent occurrence. Some- 

 times it is the consequence of hastiness or of inattention, or it is an 

 apparently plain and obvious deduction; but the ways of nature some- 

 times surpass in strangeness the ways of our reasoning. All this 

 involves the idea of accuracy in the description of natural objects, and 

 it is far from easy to give a clear and graphic conception of larvae by 

 attempting lo represent its physical characteristics in words. The 

 observer should not be content merely to describe the ornamentation 

 of larvae, but should endeavor to give, in a clear and concise loord 

 •picture, a definite conception of its form, clothing, and external pecu- 



