THE BroLtocy or ErpHypRA SUBOPACA LOEW 575 
the more dorsal muscle comes anteriorly to the third segment and ends 
almost in the same region as does the ventral muscle. All these muscles 
in the two pairs come posteriorly into contact with the ventral longitudinal 
at the posterior end of the twelfth segment. The oblique muscles are 
separated in each segment, from the fourth to the twelfth. In each 
segment there are three pairs of internal dorso-lateral oblique muscles 
and three pairs of external muscles. Likewise, there are both internal 
and extérnal ventro-lateral oblique muscles, but only one pair of each. 
Two pairs of internal ventral oblique muscles and one pair of external 
ventral oblique muscles are found in each abdominal segment except 
the twelfth. The demi-annular muscles are found in each segment. 
There are four pairs in segments 5 to 11, inclusive, while in the other 
segments the number varies. In the last segments the muscles that are 
connected with the anal lobes are the anal muscles (Plate LVI, 31 and 32). 
The alimentary system.— The alimentary system consists of the tract 
and its appendages. The alimentary tract in the mature larva is about 
three times as long as the entire body. The different parts of the tract 
are distinctly marked out by constrictions or by the insertions of the 
appendages. 
The mouth opens ventrally at the anterior end, bordered by two oval 
lobes. The mandibular sclerites are exposed, each bearing a series of 
“teeth ” resembling a comb. The hyposternal sclerites are set posteriorly 
inside the oval cavity, but they are invisible through the semi-transparent 
skin. Four pairs of large chitinous tubercles are arranged in two series 
close beside the oval cavity, and lateral to them are four series of smaller 
ones. ‘Their size increases to the last row. At the farthest cephalo-dorsal 
position are four large tubercles, two on each side of the median line, and 
still dorsad to these, another four large ones are found close to one another 
in a row, resembling the premaxillary teeth of themammals (Plate LV, 15). 
The cephalopharyngeal skeleton.— In the second instar the ‘‘skeleton ” 
is very slender. The mandibular sclerite consists of a single piece, more 
or less U-shaped and with a series of teeth, while another single piece 
composes the remainder of the skeleton. These two pieces of the whole 
skeleton are rather apart from each other but joined with each other 
through muscles. As the larva matures, the U-shaped piece breaks into 
two pieces. Dorso-caudad of them are a pair of dental sclerites and a 
pair of slender chitinous plates. A pair of hypostomal sclerites are 
