THE NATURAL ENEMIES OF THE CITRUS MEALY BUG II 263 



Metathorax — Crescent-shaped with tlie convex surface towards the front ; 

 equal to or slightly exceeding the mesothorax in length and greater in width. 

 Much narrower on the posterior margin than on the anterior. 



Abdomen — Commonly very convex along the median line ; somewhat 

 flattened out on the lateral joints (sutures between the segments). In many 

 of the nymphs there is a deep suture between the segments 3 and 4, 4 and 5, 

 5 and 6, and sometimes between 6 and 7. These transverse sutures or joints, 

 permit a greater flexibility of the abdomen, in virtue of which the nymph is 

 able to raise itself almost perpendicular to the surface to which it is attached 

 and to repeat this motion in a regular manner, when it is molested. This is 

 to frighten its enemies. The lateral portions and the flattenings of the ab- 

 dominal segments are prolonged sometimes, more or less, by spines, which is 

 true of some segments of the nymphs of the genus Aiiatis. 



Anal Appendage — Absent, but the apex of the abdomen is prolonged to 

 a point forming in many of the nymphs an anal fork which is sometimes 

 folded under the dorsum. This anal fork first observed by Letzner (1857) 

 serves to hold the nymph in the skin of the larva and is easily broken when 

 the nymph is forced violently from its binding, leaving the abdomen rounded. 

 This anal fork (morphologically considered) is like that of the nymphs and 

 larvae of the Cassidini, a subfamily of the Chrysomelidse. 



Ventral View — Head small, border of the anterior margins of the pro- 

 thorax as it occurs in many of the nymphs of the Clavicornia. The large 

 maxillary palpi, which are easily distinguished by the terminal article which 

 is nearly triangular or the shape of an axe. The rest of the mouth-parts are 

 not very conspicuous. The antennae are visible from both sides of the head, 

 resting in the cavity formed by the lateral margins of the prothorax. 



Feet — The pair of anterior feet and the mesothoracic ones are doubled 

 contiguously below the anterior part of the nymph, but are so small that 

 the knees do not protrude from the sides of the nymph. The femur forms 

 nearly a right angle with the main axis of the body. The metathoracic feet 

 are almost hidden by the elytra. 



Cryptolaemus montrouzieri 



Eggs — Are orange-colored and long, tapering to a point at both ends. 

 They are laid on end and stand together like a bunch of cigars. There are 

 from 4 to 12 in each bunch, and they are laid on various parts of the tree, 

 on the bark of the limbs and trunk in hidden places, on the leaves and 

 even on the stems of the fruit. The eggs hatch out very soon. It has been 

 impossible to keep those collected in the field from hatching for over one 

 week. The eggs probably remain for sometime in cold weather, but under 

 favorable conditions should hatch within two weeks. 



Larva; (Fig. 106 A) : Hatch all at about the same time, and immediately 

 go in search of food. The first born have little covering, and the legs are 

 very prominent. Length about 1 mm. Form, oblong to oblong oval. The 

 body when covered with the white, wooly secretion is of various shapes, 

 but usually longer than wide. The length of the body proper when fully 



