FB2025_05 , released December 11, 2025
FB2025_05 , released December 11, 2025
CV Term Report
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General Information
Term embryonic/larval lymph gland ID (Ontology) FBbt:00001668 (Fly Anatomy)
Definition Hematopoietic organ of the larva, located along the dorsal vessel, behind the brain. It produces the plasmatocytes, crystal cells and lamellocytes which are released at the end of the larval instar and onset of metamorphosis. It is composed of 3 pairs of bilateral lobes: an anterior primary lobe, a posterior secondary lobe and the most posterior lobe (or multiple lobes), the tertiary lobe. Each lobe is separated by pericardial cells. In the late embryo, the lymph gland consists of a single pair of lobes (primary lobes) containing around 20 cells each that flank the dorsal vessel. By the second larval instar, the lymph gland is composed of two or three new pairs of posterior lobes, and the primary lobes have increased in size to contain around 200 cells. During the first and early second larval instars, the lymph gland comprises only the hematopoietic progenitor population. The lymph gland increases in size ten-fold by the late third instar, and at this stage the progenitor cells (prohemocytes) become restricted to the medial region (medullary zone) of the primary lobe and become quiescent. The differentiated hemocytes are found in the periphery (cortical zone) of the primary lobe and these cells proliferate extensively. The posterior signaling center is a group of about 30 cells at the posterior tip of the primary lobe that secretes several signaling molecules and functions as a stem-cell niche. The secondary and tertiary lobes contain prohemocytes, and rarely a differentiated cell. Lymph glands are eliminated at metamorphosis.[ FlyBase:FBrf0031001 FlyBase:FBrf0032406 FlyBase:FBrf0074444 FlyBase:FBrf0155787 FlyBase:FBrf0162082 FlyBase:FBrf0187467 ]
Also Known As "embryonic/larval hematopoietic organ"
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Annotations
Records annotated with this term OR any of its CHILD TERMS
Records annotated with this exact term (annotations to child terms are NOT included)
Data Class Field Records
Alleles (FBal)  PHENOTYPE_MANIFEST_IN     199
Insertions (FBti)  EXPRESSION_STAGE_TISSUE_POSITION      90
Insertions (FBti)  PHENOTYPE_MANIFEST_IN      44
Constructs (FBtp)  PHENOTYPE_MANIFEST_IN      85
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 Full annotation statements 
Relevant FlyBase reports
 Alleles Genes Insertions Constructs
 embryonic/larval lymph gland (all annotations which use CV term, excluding "NOT" statements)     201    152    134     97
     embryonic/larval lymph gland | cell non-autonomous | somatic clone | third instar larval stage       3       --       1      2
     embryonic/larval lymph gland | embryonic stage       2       --       --       --
     embryonic/larval lymph gland | first instar larval stage       2       --       --       2
     embryonic/larval lymph gland | larval stage      35       --       1     21
     embryonic/larval lymph gland | larval stage | conditional       3       --       --       1
     embryonic/larval lymph gland | larval stage | heat sensitive       3       --       --       4
     embryonic/larval lymph gland | second instar larval stage       6       --       1      2
     embryonic/larval lymph gland | somatic clone       1       --       --       --
     embryonic/larval lymph gland | third instar larval stage      19       --       --      10
Spanning Tree (Parents/Children)
Only view relationship: 
mesodermal derivative
 |__trunk mesoderm derivative__
multicellular structure        |
 |__multi-tissue structure_____|
                               embryonic/larval lymph gland  752 rec.
                                |__primary lobe of embryonic/larval lymph gland 226 rec.
                                |__secondary lobe of embryonic/larval lymph gland 67 rec.
                                |__tertiary lobe of embryonic/larval lymph gland 32 rec.
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Is a multi-tissue structure
trunk mesoderm derivative
Develops from lymph gland primordium
Part of larval circulatory system
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UBERON:6001668