222 The University Science Bulletin. 



edge usually bears teeth, which may extend for its entire length, be 

 confined to the apical half, or appear only at the tip. The teeth 

 are of various shapes in the different species, and may or may not 

 in turn bear secondary teeth. The pointed tip is usually notched 

 with small teeth, and these may appear on either the dorsal or ven- 

 tral or both sides. From the interior of the valve certain ductlike 

 structures lead to the dorsal and apical teeth. The function of these 

 ducts is unknown. This pair of valves is usually united one to the 

 other basally, sometimes by a heavy chitinized connection, some- 

 times only by a membrane, but not by a tongue and groove. 



Valve III is the most caudal in attachment, being attached to the 

 caudal end of the same sclerite to which valve II is attached. There 

 is also a membranous connection between this valve and the ventral 

 side of the pygofer for about h;ilf the length of the valve. The 

 proximal half of the valve is narrow and the apical half broad and 

 spoonlike, being somewhat concave on its inner surface. It is 

 bluntly rounded at the apex. This pair of valves, between which 

 there is no connection, forms a protecting sheath in which the ovi- 

 positor is completely encased when not in use. 



Oviposition of Cicadella hieroglyphica (Say) has been observed 

 and the use of the ovipositor noted. Valve III remains in its posi- 

 tion in the groove of segment nine and takes no part in the opera- 

 tion. Valves I and II, closely appressed and appearing as a single 

 structure, are extruded from their resting place and form the func- 

 tional part of the ovipositor. The ovipositor is first held vertically 

 and its tip inserted under the epidermis of the leaf. It is then 

 pushed in to nearly its full length, and now is in a horizontal posi- 

 tion, the flat surface of the ovipositor being parallel with the flat 

 surface of the leaf. The teeth on the dorsal edge of the ovipositor 

 are now turned cephalad. The ovipositor is pushed backward and 

 forward with a sawlike motion until the chamber is large enough for 

 the reception of the egg. The egg passes out between the valves of 

 the ovipositor and into the chamber, and when in place, the oviposi- 

 tor is withdrawn and folded into its resting place. 



* 



TAXONOMIC USE OF THE OVIPOSITOR. 



In the search for characters of taxonomic value in the ovipositor, 

 valve II was at once hit upon as being the structure most likely to 

 possess useful characters. It varies in different species in regard to 

 size, shape, number and shape of primary teeth, number and shape 

 of the secondary teeth borne by the primary teeth, characters of the 

 tip, and in the number and arrangement of the ducts. That these 



