244 HOUSE, GARDEN, AND FIELD 



strong, tooth-like prominences, and the labrum, a flap 

 which covers in the front of the mouth. A close observer 

 can tell by the details of the antenna whether the head so 

 displayed is that of a male or of a female cockroach. 



Next put the hind half of the head into the lantern. 

 Point out that there are now seen two other pairs of 

 jaws, called maxillae. The fore pair of these are quite 

 separate from one another ; the hind pair are smaller 

 and united at the base. Each of the four maxillae bears 

 a slender, jointed palp, which is used by the insect to 

 examine its food. How does the palp differ in the two 

 maxillae ? What are the most obvious differences between 

 the feeding organs of a cockroach and those of a man, a 

 snail, a crayfish, or any other animal known to the class ? 



One of the legs may be mounted in the same way, 

 and shown by the lantern-microscope, or studied with 

 a simple lens. Do not plague a class of children with 

 Latin names for the joints of the legs, and do not name 

 them at all unless you foresee that the names will be 

 necessary, or at least convenient, in the present stage of 

 your work. 



Extend the wing-covers and wings, if your cockroach 

 possesses them. In the common cockroach of the kitchen 

 only the male has them well-developed. The large 

 American cockroach, which is now supplied by many 

 dealers, has the wings well-developed in both sexes. Note 

 that the fore-wing (wing-cover) is attached to the mid- 

 thorax, the hind-wing to the hind-thorax. The wing- 

 covers, if well-developed, are stiff and cannot be folded ; 

 when at rest one overlies the other ; the membranous 

 wings are folded fan -wise. The female of the common 

 cockroach has short and quite useless wing-covers, and 

 instead of wings we find only a slight branched pattern, 

 stamped, as it were, upon the back of the thorax.- 



The upper half of a cockroach abdomen, which has 

 been cleared with potash, may be displayed in the lantern. 

 Observe the segments, the flexible membranes by which 



