Biology of the Membra cidae of the CA^iXGA Lake Basin 367 



OVIPOSITION 



There are a number of rather distinct types of oviposition, as regards 

 both the location of the eggs and the mechanics of the process. The 

 eggs are most commonly deposited under the bark of the younger twigs, 

 generally in wood one, two, or in some cases three years old. In most 

 cases a single narrow slit is made in the bark, the ovipositor not reaching 

 the cambium or, if reaching it, shpping down on one side of the twig 

 between the bark and the wood and not penetrating the xylem. In this 

 sHt the eggs are deposited and the bark springs back into place over 

 them. This type of oviposition is illustrated by most of the species of the 

 genera Telamona, Carynota, Cyrtolobus, and Glossonotus. By this 

 method Uttle damage is done to the host, as the injury is not a severe one 

 and quickly heals. Another type of twig oviposition is found in certain 

 species of the genus Ceresa, of which C. hubalus is a well-known example. 

 This species makes a curved slit in the bark, and another close beside it 

 in such a fashion (Plate xxiv, 7, page 223) that the wound fails to close 

 and not only affects the growth of the stem but affords entrance for various 

 fungi and for other insects. A similar type of injury has been reported for 

 certain species of Stictocephala on herbaceous stems, in which cases 

 if the stems are small they may be punctured to such an extent as to cause 

 them to break off at the point of injury. 



A number of species deposit in the buds of the host. In tliis type of 

 oviposition the eggs are laid just beneath the outer bud scales and the 

 nymphs emerge at the time when these scales are first opening in the 

 spring. In a few cases the eggs are not entirely covered but project 

 slightly out of the bud tissue. This method of oviposition has little 

 injurious effect on the host, since the outer bud scale, being entirely 

 protective, may be damaged without injuring the plant. In the case 

 of fruit buds the injuiy may be more serious, but in no case has it appeared 

 to an extent great enough to be considered important. The most abun- 

 dant of the species that oviposit in the bud are Ceresa taurina, Ceresa 

 borealis, Enchenopa hinotata, and Vanduzea arquata. 



A few species lay their eggs in the leaves. This is notably true of 

 Entylia badriana and Publilia concava. The underside of the leaf is 

 chosen for oviposition and the eggs are placed in two rows, one on each 

 side of the midrib. The egg is not entirely within the leaf but the tip 



