THE LEAD-CABLE BORER IN CALIFORNIA. 53 



Tenth abdominal segment: Much smaller than ninth, hardly one-fifth its size; 

 truncate. Anal opening (PI. I, Fig. 16) longitudinal; between two oval anal 

 lobes. 



Spiracles (PI. II, Fig. 32) : Nine; bilabiate, with slightly ehitinized peritreme; 

 elongate oval, more than three times as long as wide ; longest diameter extend- 

 ing dorso-ventrally. Spiracular opening set all around with stiff, hairlike spines 

 reaching half way to opening's longest diameter. First (mesothoracic) spiracle 

 larger than the rest ; located in the epipleurum of prothorax. Abdominal 

 spiracles all of same size and all placed alike, near lower margin of terga. 



Body movements:'^ Very active. 



Remarks Refeering to the Deviating Morphological Structures of the 



First-Stage Larva. 



PI. I, Figs. 1-7, 9-12. 



Length of larva: Three-sevenths the length of the egg; same width as egg. 

 Average length without spine, 0.76 millimeter ; with spine, 0.83 millimeter ; 

 length of exposed part of head, 0.10 millimeter. Width of head, 0.17 milli- 

 meter ; of prothorax, 0.86 millimeter ; of the middle of body, 0.24 millimeter ; 

 of ninth abdominal segment, 0.10 millimeter. 



Labrum (PI. I, Fig. 3) : Subtriangular, divided as in mature larva by two 

 longitudinal, parallel bands into three divisions. Setae straight, comparatively 

 longer than in mature larva, fewer than in this. 



Antenna (PI. I, Figs. 2 and 4) : Very short, consisting of a flat and ovate 

 basal membrane carrying a single small joint (a) with a separate low basal 

 ring (b) and a slightly smaller supplementary joint (c). 



Mandible (PI. I, Fig. 4) : Apex formed by two flat, blunt, curved, anteriorly 

 converging, toothlike thickenings of almost equal size and shape, one thicken- 

 ing dorsal (a), the other ventral (&), united by a thin chitinous wall (c), pos- 

 sibly corresponding to the thin wall of the anterior mandibular cavity in the 

 mature larva. Biting surface (d) flat, disklike, with free, slightly projecting 

 anterior and lateral margins. Color of entire mandible light brown. 



Ventral mouthparts (Maxilla, labium, mentum, and submentum) (PL I, 

 Figs. 4, 5, 6) : All essential morphological features as in mature larva; the 

 proportions of the different structures, however, somewhat deviating; the com- 

 paratively large size of ligula (li, PI. I, Fig. 6) especially noticeable. 



Legs (PI. I, Figs. 10, 11, 12) : Very reduced. First pair (I) with two indis- 

 tinctly separated joints; about five setse. Second pair (II) wart shaped; with 

 two setse. Third pair (III) almost absent, represented by minute conical ele- 

 vation of the skin ; with one small seta. 



Body form (PI. I, Fig. 1): Orthosomatic, clavate-cylindrical, tapering from 

 prothorax ; rates of height of thorax to height of an average abdominal segment 

 as 4 : 3. Dorsally plicate, with plicfe arranged as in mature larva. 



Body color, cMtinizations, and setoe (PI. I, Fig. 1) : Shiny white, with gran- 

 ulated appearance. Soft ; chitinous rod present on prothorax. No setse. 



Ninth abdominal segment (PI. I, Fig. 7) : Dorsally longer than eighth. Ter- 

 minal half armed with chitinous and yellowish, unpaired, depressed, triangular 

 tail spur, at end abruptly truncate and on each side posteriorly serrate ; a few 

 scattered setse. 



Tenth abdominal segment (PI. I, Fig. 1) : Completely covered by armed 

 ninth. Anal opening, a longitudinal slit. 



Body movements: Sluggish. 



The most striking characters of the first-stage larva are the orthosomatic 

 body shape, the apparently apically bilobe<i mandible, the rudimentary legs, and 

 the tail spur on the ninth abdominal segment. 



According to recent observations by Dr. T, E. Snyder on the differ- 

 ent stages of Lyctus planicoUis Lee, corresponding characters are 

 found in the first-stage larva of this genus, namely, a straight, ortho- 

 somatic body as compared with the curved cyrtosomatic body of the 

 other stages, rudimentary legs as compared with the well developed 

 legs of the other stages, and, instead of an unpaired tail spur as in 

 Scobicia, a pair of short, conical, slightly upward curved, pointed 



21 For further information on the habits of the different larval stages see pages l-'i-lG. 



