MEDITERRANEAN FRUIT FLY IN HAWAII. 



87 



pits; scutellum smooth with 3 or 4 small pits and a large deep one; metanotum with a 

 short median carina, on the submedian part shortly crenulate before the sublateral 

 pit; propodeum with a median carina, in some specimens divided from the base into 

 two almost contiguous parallel arms posteriorly diverging, the remainder rugose; 

 mesopleural sulcus f alveolate. Wings with venation as shown in figure [PI. XX, fig. 1.] 

 Abdomen with the first segment rugose on the dorsum, the remainder smooth, with 

 a few hairs; ovipositor almost straight, a little shorter than the abdomen. 



Length of body, 2.6 mm.; width of thorax, 0.79 mm.; length of antennae, 3.3 mm.; 

 length of front wing, 2.6 mm.; width of same, 1.15 mm.; length of third pair legs, 2 

 mm.; length of ovipositor, 1.15 mm. 



Egg. — The egg when first deposited is about 0.45 mm. long, white 

 and of the shape indicated in fig. 19, a. As the embryo develops, the 

 entire egg increases in size 

 until when between 2 and 3 

 days old (Feb., 1916) it be- 

 comes about 0.8 mm. long, 

 and over twice as wide as 

 when first deposited, with a 

 protuberance at the anterior 

 end. The developing em- 

 bryo may be readily seen 

 through the egg membranes 

 (fig. 19, h). 



Larva. — The white, newly 

 hatched larva is about 1 mm. 

 long. It has a rather large 

 head and 12 distinct body 

 segments. (See fig. 20.) On 

 the anterior ventral portion 

 of the first body segment is 

 a pair of appendages (fig. 20, 

 b, d), which the larva does 

 not appear to be able to move 

 at will or to use as an aid to 

 locomotion. The jaws are very large and strong, being much larger 

 in proportion than in the succeeding instars (fig. 20, c). The ven- 

 tral portion of the head, behind the mandibles, is rather strongly 

 chitinized, forms a support for the latter, and bears on its anterior 

 margin two toothlike projections. On the ventral anterior portion 

 of the head are two fleshy antenna! protuberances. The thoracic 

 appendages and large mandibles are lost after the larva molts into 

 the second instar. 



Pupa. — The pupa is about 2.3 mm. long (fig. 21). It is very 

 readily distinguished from the other opiine pupae by the short 

 ovipositor sheath. 



Fig. 20.— Opius humilis. Larva: a, Ventral, and 6, lateral 

 view of newly hatched larva; c, ventral aspect of head of 

 d, enlarged thoracic appendage. (Original.) 



